CAllMain::RemoveFileAccessPermission

public function RemoveFileAccessPermission($path, $arGroups=false)
{
	global $CACHE_MANAGER;

	CMain::InitPathVars($site, $path);
	$DOC_ROOT = CSite::GetSiteDocRoot($site);

	$path = rtrim($path, "/");
	if($path == '')
		$path = "/";

	if(($p = bxstrrpos($path, "/")) !== false)
	{
		$path_file = mb_substr($path, $p + 1);
		$path_dir = mb_substr($path, 0, $p);
	}
	else
		return false;

	$PERM = array();
	$io = CBXVirtualIo::GetInstance();
	if (!$io->FileExists($DOC_ROOT.$path_dir."/.access.php"))
		return true;

	include($io->GetPhysicalName($DOC_ROOT.$path_dir."/.access.php"));

	$str = "$arPerm)
	{
		if($file != $path_file || $arGroups !== false)
		{
			foreach($arPerm as $group=>$perm)
			{
				$bExists = false;
				if(is_array($arGroups))
				{
					//compatibility with group id
					if(in_array($group, $arGroups))
						$bExists = true;
					elseif(preg_match('/^G[0-9]+$/', $group) && in_array(mb_substr($group, 1), $arGroups))
						$bExists = true;
					elseif(preg_match('/^[0-9]+$/', $group) && in_array('G'.$group, $arGroups))
						$bExists = true;
				}
				if($file != $path_file || ($arGroups !== false && !$bExists))
					$str .= "$PERM["".EscapePHPString($file).""]["".EscapePHPString($group).""]="".EscapePHPString($perm)."";n";
			}
		}
	}

	$str .= "?".">";

	$this->SaveFileContent($DOC_ROOT.$path_dir."/.access.php", $str);
	$CACHE_MANAGER->CleanDir("menu");
	CBitrixComponent::clearComponentCache("bitrix:menu");
	unset($this->FILE_PERMISSION_CACHE[$site."|".$path_dir."/.access.php"]);

	foreach(GetModuleEvents("main", "OnChangePermissions", true) as $arEvent)
		ExecuteModuleEventEx($arEvent, array(array($site, $path), array()));

	return true;
}