gboudreau/Greyhole

<?php
/*
Copyright 2009-2020 Guillaume Boudreau

This file is part of Greyhole.

Greyhole 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 3 of the License, or
(at your option) any later version.

Greyhole 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 Greyhole.  If not, see <http://www.gnu.org/licenses/>.
*/

class DaemonRunner extends AbstractRunner {

    public static $was_idle = TRUE;
    private static $process_is_daemon = FALSE;

    public static function isCurrentProcessDaemon() {
        return static::$process_is_daemon;
    }

    public function run() {
        // Prevent multiple daemons from running simultaneously
        if (self::isRunning()) {
            die("Found an already running Greyhole daemon with PID " . self::getPID() . ".\nCan't start multiple Greyhole daemons.\nQuitting.\n");
        }

        static::$process_is_daemon = TRUE;

        $log = "Greyhole (version %VERSION%) daemon started.";
        Log::info($log);
        $this->initialize();

        LogHook::trigger(LogHook::EVENT_TYPE_IDLE, Log::EVENT_CODE_IDLE, $log);

        $db_spool = DBSpool::getInstance();

        // The daemon runs indefinitely, this the infinite loop here.
        while (TRUE) {
            // Process the spool directory, and insert each task found there into the database spool.
            SambaSpool::parse_samba_spool();

            // Check that storage pool drives are OK (using their UUID, or .greyhole_uses_this files)
            StoragePool::check_drives();

            // Execute the next task from the tasks queue ('tasks' table in the database)
            $db_spool->execute_next_task();
        }
    }
    
    private static function isRunning() {
        $num_daemon_processes = exec('ps ax | grep "greyhole --daemon\|greyhole -D" | grep -v grep | grep -v bash | grep -v "sudo" | wc -l');
        return $num_daemon_processes > 1;
    }

    private static function getPID() {
        return exec('ps ax | grep "greyhole --daemon\|greyhole -D" | grep -v grep | grep -v bash | grep -v "sudo" | grep -v ' . getmypid() . ' | awk "{print \$1}"');
    }

    private function initialize() {
        // Check the database tables, and repair them if needed.
        DB::repairTables();

        // Creates a GUID (if one doesn't exist); will be used to uniquely identify this Greyhole install, when reporting anonymous usage to greyhole.net
        GetGUIDCliRunner::setUniqID();

        // Calculate the config file hash, and save it in DB, to be able to know if the daemon is in sync with the current greyhole.conf
        Settings::set('last_known_config_hash', get_config_hash());

        // Terminology changed (attic > trash, graveyard > metadata store, tombstones > metadata files); this requires filesystem & database changes.
        MigrationHelper::terminologyConversion();

        // For files which don't have extra copies, we at least create a copy of the metadata on a separate drive, in order to be able to identify the missing files if a hard drive fails.
        Metastores::choose_metastores_backups();

        // We backup the database settings to disk, in order to be able to restore them if the database is lost.
        Settings::backup();

        // Check that the Greyhole VFS module used by Samba is the correct one for the current Samba version. This is needed when Samba is updated to a new major version after Greyhole is installed.
        SambaUtils::samba_check_vfs();

        // Check if the in-memory spool folder exists, and if no, create it and mount a tmpfs there. VFS will write there recvfile (etc.) operations.
        SambaSpool::create_mem_spool();

        // Process the spool directory, and insert each task found there into the database.
        SambaSpool::parse_samba_spool();

        // Create the dfree cache folder, if it doesn't exist
        gh_mkdir('/var/cache/greyhole-dfree', NULL, (object) array('fileowner' => 0, 'filegroup' => 0, 'fileperms' => (int) base_convert("0777", 8, 10)));
    }

    public function finish($returnValue = 0) {
        // The daemon should never finish; it will be killed by the init script.
        // Not that it can reach finish() anyway, since it's in an infinite while(TRUE) loop in run()... :)
    }

    public static function restart_service() {
        if (is_file('/etc/init.d/greyhole')) {
            exec("/etc/init.d/greyhole restart");
            return TRUE;
        } else if (is_file('/etc/init/greyhole.conf')) {
            exec("/sbin/restart greyhole");
            return TRUE;
        } else if (is_file('/usr/bin/supervisorctl')) {
            exec("/usr/bin/supervisorctl status greyhole", $out, $return);
            if ($return === 0) {
                exec("/usr/bin/supervisorctl restart greyhole");
                return TRUE;
            }
        }
        return FALSE;
    }
}

?>