TYPO3 v15 dev-main snapshot ()

2026-08-10 22:31:09 +02:00
commit af8cc155b5
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+<?php
+
+/*
+ * This file is part of the TYPO3 CMS project.
+ *
+ * It is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License, either version 2
+ * of the License, or any later version.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE.txt file that was distributed with this source code.
+ *
+ * The TYPO3 project - inspiring people to share!
+ */
+
+namespace TYPO3\CMS\Core\Locking;
+
+use TYPO3\CMS\Core\Core\Environment;
+use TYPO3\CMS\Core\Locking\Exception\LockAcquireException;
+use TYPO3\CMS\Core\Locking\Exception\LockAcquireWouldBlockException;
+use TYPO3\CMS\Core\Locking\Exception\LockCreateException;
+use TYPO3\CMS\Core\Security\BlockSerializationTrait;
+use TYPO3\CMS\Core\Utility\GeneralUtility;
+
+/**
+ * flock() locking
+ */
+class FileLockStrategy implements LockingStrategyInterface
+{
+    use BlockSerializationTrait;
+
+    public const FILE_LOCK_FOLDER = 'lock/';
+    public const DEFAULT_PRIORITY = 75;
+
+    /**
+     * @var resource File pointer if using flock method
+     */
+    protected $filePointer;
+
+    /**
+     * @var string File used for locking
+     */
+    protected $filePath;
+
+    /**
+     * @var bool True if lock is acquired
+     */
+    protected $isAcquired = false;
+
+    /**
+     * @param string $subject ID to identify this lock in the system
+     * @throws LockCreateException if the lock could not be created
+     */
+    public function __construct($subject)
+    {
+        /*
+         * Tests if the directory for file locks is available.
+         * If not, the directory will be created. The lock path is usually
+         * below typo3temp/var, typo3temp/var itself should exist already (or root-path/var/ respectively)
+         */
+        if ($GLOBALS['TYPO3_CONF_VARS']['SYS']['locking']['strategies'][self::class]['lockFileDir'] ?? false) {
+            $path = Environment::getProjectPath() . '/'
+                . trim($GLOBALS['TYPO3_CONF_VARS']['SYS']['locking']['strategies'][self::class]['lockFileDir'], ' /')
+                . '/';
+        } else {
+            $path = Environment::getVarPath() . '/' . self::FILE_LOCK_FOLDER;
+        }
+        if (!is_dir($path)) {
+            // Not using mkdir_deep on purpose here, if typo3temp itself
+            // does not exist, this issue should be solved on a different
+            // level of the application.
+            if (!GeneralUtility::mkdir($path)) {
+                throw new LockCreateException('Cannot create directory ' . $path, 1395140007);
+            }
+        }
+        if (!is_writable($path)) {
+            throw new LockCreateException('Cannot write to directory ' . $path, 1396278700);
+        }
+        $this->filePath = $path . 'flock_' . md5((string)$subject);
+    }
+
+    /**
+     * Destructor:
+     * Releases lock automatically when instance is destroyed and release resources
+     */
+    public function __destruct()
+    {
+        $this->release();
+    }
+
+    /**
+     * Try to acquire an exclusive lock
+     *
+     * @param int $mode LOCK_CAPABILITY_EXCLUSIVE or LOCK_CAPABILITY_SHARED or self::LOCK_CAPABILITY_NOBLOCK
+     * @return bool Returns TRUE if the lock was acquired successfully
+     * @throws LockAcquireException if the lock could not be acquired
+     * @throws LockAcquireWouldBlockException if the acquire would have blocked and NOBLOCK was set
+     */
+    public function acquire($mode = self::LOCK_CAPABILITY_EXCLUSIVE)
+    {
+        if ($this->isAcquired) {
+            return true;
+        }
+
+        $filePointer = fopen($this->filePath, 'c');
+        if ($filePointer === false) {
+            throw new LockAcquireException('Lock file could not be opened', 1294586099);
+        }
+        $this->filePointer = $filePointer;
+        GeneralUtility::fixPermissions($this->filePath);
+
+        $operation = $mode & self::LOCK_CAPABILITY_EXCLUSIVE ? LOCK_EX : LOCK_SH;
+        if ($mode & self::LOCK_CAPABILITY_NOBLOCK) {
+            $operation |= LOCK_NB;
+        }
+
+        $wouldBlock = 0;
+        $this->isAcquired = flock($this->filePointer, $operation, $wouldBlock);
+
+        if (!$this->isAcquired) {
+            // Make sure to cleanup any dangling resources for this process/thread, which are not needed any longer
+            fclose($this->filePointer);
+        }
+        if ($mode & self::LOCK_CAPABILITY_NOBLOCK && !$this->isAcquired && $wouldBlock) {
+            throw new LockAcquireWouldBlockException('Failed to acquire lock because the request would block.', 1428700748);
+        }
+
+        return $this->isAcquired;
+    }
+
+    /**
+     * Release the lock
+     *
+     * @return bool Returns TRUE on success or FALSE on failure
+     */
+    public function release()
+    {
+        if (!$this->isAcquired) {
+            return true;
+        }
+        $success = true;
+        if (is_resource($this->filePointer)) {
+            if (flock($this->filePointer, LOCK_UN) === false) {
+                $success = false;
+            }
+            fclose($this->filePointer);
+        }
+        $this->isAcquired = false;
+        return $success;
+    }
+
+    /**
+     * Get status of this lock
+     *
+     * @return bool Returns TRUE if lock is acquired by this locker, FALSE otherwise
+     */
+    public function isAcquired()
+    {
+        return $this->isAcquired;
+    }
+
+    /**
+     * @return int Returns a priority for the method. 0 to 100, 100 is highest
+     */
+    public static function getPriority()
+    {
+        return $GLOBALS['TYPO3_CONF_VARS']['SYS']['locking']['strategies'][self::class]['priority']
+            ?? self::DEFAULT_PRIORITY;
+    }
+
+    /**
+     * @return int LOCK_CAPABILITY_* elements combined with bit-wise OR
+     */
+    public static function getCapabilities()
+    {
+        if (PHP_SAPI === 'isapi') {
+            // From php docs: When using a multi-threaded server API like ISAPI you may not be able to rely on flock()
+            // to protect files against other PHP scripts running in parallel threads of the same server instance!
+            return 0;
+        }
+        $capabilities = self::LOCK_CAPABILITY_EXCLUSIVE | self::LOCK_CAPABILITY_SHARED | self::LOCK_CAPABILITY_NOBLOCK;
+
+        return $capabilities;
+    }
+
+    /**
+     * Destroys the resource associated with the lock
+     */
+    public function destroy()
+    {
+        @unlink($this->filePath);
+    }
+}