[BUGFIX] Simplify Apcu cache backend identifier calculation

APCu cache backend is a shared memory per user and
typically bound to the executing posix user-id.
Calculating different cache identifiers per user
is useless since those won't share the same shm.

Resolves: #96232
Releases: master, 11.5, 10.4
Change-Id: If6b6a744828d06d55f2c9b5656aef48193da7384
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72510


Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>

typo3/sysext/core/Classes/Cache/Backend/ApcuBackend.php

@@ -95,22 +95,10 @@ class ApcuBackend extends AbstractBackend implements TaggableBackendInterface
     public function setCache(FrontendInterface $cache)
     {
         parent::setCache($cache);
-        $processUser = $this->getCurrentUserData();
-        $pathHash = md5(Environment::getProjectPath() . $processUser['name'] . $this->context . $cache->getIdentifier());
+        $pathHash = md5(Environment::getProjectPath() . $this->context . $cache->getIdentifier());
         $this->setIdentifierPrefix('TYPO3_' . $pathHash);
     }
 
-    /**
-     * Returns the current user data with posix_getpwuid or a default structure when
-     * posix_getpwuid is not available.
-     *
-     * @return array
-     */
-    protected function getCurrentUserData()
-    {
-        return extension_loaded('posix') ? posix_getpwuid(posix_geteuid()) : ['name' => 'default'];
-    }
-
     /**
      * Saves data in the cache.
      *