codysnider / tt-rss

update_daemon2.php

#!/usr/bin/env php
<?php
set_include_path(dirname(__FILE__).DIRECTORY_SEPARATOR."include".PATH_SEPARATOR.
    get_include_path());

declare(ticks=1);
chdir(dirname(__FILE__));

define('DISABLE_SESSIONS', true);

require_once "autoload.php";
require_once "functions.php";
require_once "config.php";

// defaults
define_default('PURGE_INTERVAL', 3600); // seconds
define_default('MAX_CHILD_RUNTIME', 1800); // seconds
define_default('MAX_JOBS', 2);
define_default('SPAWN_INTERVAL', DAEMON_SLEEP_INTERVAL); // seconds

require_once "sanity_check.php";
require_once "db.php";
require_once "db-prefs.php";

if (!function_exists('pcntl_fork')) {
    die("error: This script requires PHP compiled with PCNTL module.\n");
}

$options = getopt("");

if (!is_array($options)) {
    die("error: getopt() failed. ".
        "Most probably you are using PHP CGI to run this script ".
        "instead of required PHP CLI. Check tt-rss wiki page on updating feeds for ".
        "additional information.\n");
}


$master_handlers_installed = false;

$children = array();
$ctimes = array();

$last_checkpoint = -1;

function reap_children() {
    global $children;
    global $ctimes;

    $tmp = array();

    foreach ($children as $pid) {
        if (pcntl_waitpid($pid, $status, WNOHANG) != $pid) {

            if (file_is_locked("update_daemon-$pid.lock")) {
                array_push($tmp, $pid);
            } else {
                Debug::log("[reap_children] child $pid seems active but lockfile is unlocked.");
                unset($ctimes[$pid]);

            }
        } else {
            Debug::log("[reap_children] child $pid reaped.");
            unset($ctimes[$pid]);
        }
    }

    $children = $tmp;

    return count($tmp);
}

function check_ctimes() {
    global $ctimes;

    foreach (array_keys($ctimes) as $pid) {
        $started = $ctimes[$pid];

        if (time() - $started > MAX_CHILD_RUNTIME) {
            Debug::log("[MASTER] child process $pid seems to be stuck, aborting...");
            posix_kill($pid, SIGKILL);
        }
    }
}

function sigchld_handler($signal) {

The parameter $signal is not used and could be removed.

    $running_jobs = reap_children();

    Debug::log("[SIGCHLD] jobs left: $running_jobs");

    pcntl_waitpid(-1, $status, WNOHANG);
}

function shutdown($caller_pid) {
    if ($caller_pid == posix_getpid()) {
        if (file_exists(LOCK_DIRECTORY."/update_daemon.lock")) {
            Debug::log("removing lockfile (master)...");
            unlink(LOCK_DIRECTORY."/update_daemon.lock");
        }
    }
}

function task_shutdown() {
    $pid = posix_getpid();

    if (file_exists(LOCK_DIRECTORY."/update_daemon-$pid.lock")) {
        Debug::log("removing lockfile ($pid)...");
        unlink(LOCK_DIRECTORY."/update_daemon-$pid.lock");
    }
}

function sigint_handler() {
    Debug::log("[MASTER] SIG_INT received.\n");
    shutdown(posix_getpid());
    die;
}

function task_sigint_handler() {
    Debug::log("[TASK] SIG_INT received.\n");
    task_shutdown();
    die;
}

pcntl_signal(SIGCHLD, 'sigchld_handler');

$longopts = array(
    "log:",
    "log-level:",
    "tasks:",
    "interval:",
    "quiet",
    "help"
);

$options = getopt("", $longopts);

if (isset($options["help"])) {
    print "Tiny Tiny RSS update daemon.\n\n";
    print "Options:\n";
    print "  --log FILE           - log messages to FILE\n";
    print "  --log-level N        - log verbosity level\n";
    print "  --tasks N            - amount of update tasks to spawn\n";
    print "                         default: ".MAX_JOBS."\n";
    print "  --interval N         - task spawn interval\n";
    print "                         default: ".SPAWN_INTERVAL." seconds.\n";
    print "  --quiet              - don't output messages to stdout\n";
    return;
}

Debug::set_enabled(true);

if (isset($options["log-level"])) {
    Debug::set_loglevel((int) $options["log-level"]);
}

if (isset($options["log"])) {
    Debug::set_quiet(isset($options['quiet']));
    Debug::set_logfile($options["log"]);
    Debug::log("Logging to ".$options["log"]);
} else {
    if (isset($options['quiet'])) {
        Debug::set_loglevel(Debug::$LOG_DISABLED);
    }
}

if (isset($options["tasks"])) {
    Debug::log("Set to spawn ".$options["tasks"]." children.");
    $max_jobs = $options["tasks"];
} else {
    $max_jobs = MAX_JOBS;
}

if (isset($options["interval"])) {
    Debug::log("Spawn interval: ".$options["interval"]." seconds.");
    $spawn_interval = $options["interval"];
} else {
    $spawn_interval = SPAWN_INTERVAL;
}

// let's enforce a minimum spawn interval as to not forkbomb the host
$spawn_interval = max(60, $spawn_interval);
Debug::log("Spawn interval: $spawn_interval sec");

if (file_is_locked("update_daemon.lock")) {
    die("error: Can't create lockfile. ".
        "Maybe another daemon is already running.\n");
}

// Try to lock a file in order to avoid concurrent update.
$lock_handle = make_lockfile("update_daemon.lock");

if (!$lock_handle) {
    die("error: Can't create lockfile. ".
        "Maybe another daemon is already running.\n");
}

$schema_version = get_schema_version();

if ($schema_version != SCHEMA_VERSION) {
    die("Schema version is wrong, please upgrade the database.\n");
}

// Protip: children close shared database handle when terminating, it's a bad idea to
// do database stuff on main process from now on.

while (true) {

    // Since sleep is interupted by SIGCHLD, we need another way to
    // respect the spawn interval
    $next_spawn = $last_checkpoint + $spawn_interval - time();

    if ($next_spawn % 60 == 0) {
        $running_jobs = count($children);
        Debug::log("[MASTER] active jobs: $running_jobs, next spawn at $next_spawn sec.");
    }

    if ($last_checkpoint + $spawn_interval < time()) {
        check_ctimes();
        reap_children();

        for ($j = count($children); $j < $max_jobs; $j++) {
            $pid = pcntl_fork();
            if ($pid == -1) {
                die("fork failed!\n");
            } else if ($pid) {

                if (!$master_handlers_installed) {
                    Debug::log("[MASTER] installing shutdown handlers");
                    pcntl_signal(SIGINT, 'sigint_handler');
                    pcntl_signal(SIGTERM, 'sigint_handler');
                    register_shutdown_function('shutdown', posix_getpid());
                    $master_handlers_installed = true;
                }

                Debug::log("[MASTER] spawned client $j [PID:$pid]...");
                array_push($children, $pid);
                $ctimes[$pid] = time();
            } else {
                pcntl_signal(SIGCHLD, SIG_IGN);
                pcntl_signal(SIGINT, 'task_sigint_handler');

                register_shutdown_function('task_shutdown');

                $quiet = (isset($options["quiet"])) ? "--quiet" : "";
                $log = function_exists("flock") && isset($options['log']) ? '--log '.$options['log'] : '';

                $my_pid = posix_getpid();

                passthru(PHP_EXECUTABLE." update.php --daemon-loop $quiet $log --task $j --pidlock $my_pid");

                sleep(1);

                // We exit in order to avoid fork bombing.
                exit(0);
            }
        }
        $last_checkpoint = time();
    }
    sleep(1);
}