<?php
/* calc.php - NeonServ v5.6
 * Copyright (C) 2011-2012  Philipp Kreil (pk910)
 * 
 * This program 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.
 * 
 * This program 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 this program. If not, see <http://www.gnu.org/licenses/>. 
 */

$text = implode(" ", array_slice($argv, 1));

$descriptor = array(0 => array("pipe", "r"),1 => array("pipe", "w"),2 => array("pipe", "w"));
$proc = proc_open('bc -l -q', $descriptor, $pipes);

if(!is_resource($proc)) {
    echo"internal calc error - please contact an administrator.\n";
    die();
}

fwrite($pipes[0], $text."\nquit\n");

$start = time();

$read=array($pipes[1]);
$write=NULL;
$except=NULL;

while(1) {
    $data = proc_get_status($proc);
    if(!$data['running']) {
        $out="";
        while(!feof($pipes[1])) { 
            $out .= fgets($pipes[1], 128); 
        }
        if($out == "") {
            $out="\0034";
            while(!feof($pipes[2])) { 
                $out .= fgets($pipes[2], 128); 
            }
            $out.="";
        }
        $out=str_replace("\n","",$out);
        $out=str_replace("\r","",$out);
        $out=str_replace("\\","",$out);
        
        if(strlen($text) > 20) {
            if(strlen($out) > 450) {
                echo "output too long (".strlen($out).")\n";
            } else {
                echo "".$text."\n";
                echo $out."\n";
            }
        } else {
            $fout="".$text." = ".$out;
            if(strlen($fout) > 450) {
                echo "output too long (".strlen($out).")";
            } else {
                echo $fout."\n";
            }
        }
        
        fclose($pipes[0]);
        fclose($pipes[1]);
        fclose($pipes[2]);
        proc_close($proc);
        
        die();
    } else {
        
        if($start+3 > time()) {
            usleep(200000); //200ms
        } else {
            //TIMEOUT
            fclose($pipes[0]);
            fclose($pipes[1]);
            fclose($pipes[2]);
            //can't simply use proc_terminate: https://bugs.php.net/bug.php?id=39992
            $ppid = $data['pid'];
            //use ps to get all the children of this process, and kill them
            $pids = preg_split('/\s+/', `ps -o pid --no-heading --ppid $ppid`);
            foreach($pids as $pid) {
                if(is_numeric($pid)) {
                    posix_kill($pid, 9); //SIGKILL signal
                }
            }
            proc_close($proc); 
            echo "calculator timeout. (maximum of 3 seconds exceeded)\n";
            die();
        }
    }
}

?>