Bug demonstration script for PHP/libevent 0.0.4 Segfault.

libevent-segfault.php

<?php
/**
 * Run this  script as-is  and it will  segfault.  My setup  is Ubuntu
 * 11.10, library details:
 *
 * php5-cli : 5.3.6-13ubuntu3.6   (output from dpkg -l)
 * libevent : 0.0.5   beta        (output from pecl list)
 * php-pear : 5.3.6-13ubuntu3.6   (output from dpkg -l)
 *
 * There are 2 things you can do to stop the segfault:
 *
 * 1.  Comment out the given line in ELoop->checkAddEvent()
 * 2.  Only add a single client to the loop
 */
class ELoop
{
    private $evBase;
    private $clients = array();

    function addClient ($client) {
        $this->clients[] = $client;
    }
    function loop () {
        $this->initLibevent();
        $hasWork = false;
        foreach ($this->clients as $c) {
            if ($ev = $this->checkAddEvent($c)) {
                $hasWork = true;
            }
        }
        if ($hasWork) {
            event_base_loop($this->evBase);
        }
    }
    private function checkAddEvent ($c, $ev=null) {
        $flags = 0;
        if ($c->canRead())
            $flags = $flags | EV_READ;
        if ($c->canWrite())
            $flags = $flags | EV_WRITE;
        if (! $flags) {
            if ($ev) {
                event_del($ev);
                event_free($ev); // Comment this line and the segfault doesn't happen
            }
            if (false === ($i = array_search($c, $this->clients))) {
                throw new \Exception("Failed to locate client within local collection during removal", 9062);
            } else {
                unset($this->clients[$i]);
            }
            return;
        }
        if (! $ev)
            $ev = event_new();
        event_set($ev, $c->getSocketHandle(), $flags, array($this, 'loopEventDispatch'), array($c, $ev));
        event_base_set($ev, $this->evBase);
        event_add($ev);
        return $ev;
    }
    function loopEventDispatch ($fd, $events, $params) {
        list($client, $event) = $params;
        if ($events & EV_READ)
            $client->read();
        if ($events & EV_WRITE)
            $client->write();
        $this->checkAddEvent($client, $event);
    }
    private function initLibevent () {
        $this->evBase = event_base_new();
    }
}

class SocketClient
{
    private $host, $port, $sock;

    function open ($host, $port) {
        $this->host = $host;
        $this->port = $port;
        if (! ($this->sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP))) {
            throw new \Exception("Failed to create inet socket", 7895);
        } else if (! socket_connect($this->sock, $this->host, $this->port)) {
            throw new \Exception("Failed to connect inet socket ({$this->host}, {$this->port})", 7564);
        } else if (! socket_set_nonblock($this->sock)) {
            throw new \Exception("Failed to switch connection in to non-blocking mode.", 2357);
        }
    }
    function getSocketHandle () {
        return $this->sock;
    }
    function read () {
        $buff = '';
        while (@socket_recv($this->sock, $tmp, 4096, MSG_DONTWAIT)) {
            $buff .= $tmp;
        }
        return $buff;
    }
    function write ($buff='') {
        if (($tmp = socket_write($this->sock, $buff)) === false) {
            throw new \Exception(sprintf("Socket write failed: %s",
                                         socket_strerror(socket_last_error($this->sock))), 7854);
        }
    }
}
class HttpClient extends SocketClient
{
    private $state = 0, $domain;

    function __construct ($domain) {
        $ip = gethostbyname($domain);
        if ($ip == $domain) {
            throw new \Exception("Failed to resolve HTTP host", 2351);
        }
        $this->open($ip, 80);
        $this->domain = $domain;
    }
    function canRead () {
        switch ($this->state) {
        case 1:
            return true;
        default:
            return false;
        }
    }
    function canWrite () {
        switch ($this->state) {
        case 0:
            return true;
        default:
            return false;
        }
    }
    function read () {
        $this->state = 2;
        $buff = parent::read();
        printf("[http] Reads response (%d):\n%s\n", strlen($buff), substr($buff, 0, strpos($buff, "\r\n")));
    }
    function write ($buff='') {
        if ($this->state == 0) {
            // Write HTTP header.
            parent::write("GET / HTTP/1.1\r\nHost: {$this->domain}\r\n" .
                          "Connection: close\r\n" .
                          "User-Agent: php libevent test\r\n" .
                          "Accept-Charset: ISO-8859-1,UTF-8;q=0.7,*;q=0.7\r\n" .
                          "Cache-Control: no-cache\r\n" .
                          "Accept-Language: de,en;q=0.7,en-us;q=0.3\r\n\r\n");
            $this->state = 1;
        }
    }
}
$el = new ELoop;
$el->addClient(new HttpClient('microsoft.com'));
$el->addClient(new HttpClient('bluelines.org'));
$el->loop();