[moodle.git] / lib / uploadlib.php

<?php
error_reporting(E_ALL ^ E_NOTICE);
/**
 * This class handles all aspects of fileuploading 
 */
class upload_manager {

    var $files; // array to hold local copies of stuff in $_FILES
    var $config; // holds all configuration stuff.
    var $status; // keep track of if we're ok (errors for each file are kept in $files['whatever']['uploadlog']
    var $course; // the course this file has been uploaded for (for logging and virus notifications)
    var $inputname; // if we're only getting one file.

    /**
     * Constructor, sets up configuration stuff so we know how to act.
     * Note: destination not taken as parameter as some modules want to use the insertid in the path and we need to check the other stuff first.
     * @param $inputname - if this is given the upload manager will only process the file in $_FILES with this name.
     * @param $deleteothers - whether to delete other files in the destination directory (optional,defaults to false)
     * @param $handlecollisions - whether to use handle_filename_collision() or not. (optional, defaults to false)
     * @param $course - the course the files are being uploaded for (for logging and virus notifications)
     * @param $recoverifmultiple - if we come across a virus, or if a file doesn't validate or whatever, do we continue? optional, defaults to true.
     * @param $modbytes - max bytes for this module - this and $course->maxbytes are used to get the maxbytes to use (lowest) from get_max_upload_file_size().
     */
    function upload_manager($inputname='',$deleteothers=false,$handlecollisions=false,$course=null,$recoverifmultiple=false,$modbytes=0) {
        
        global $CFG;
        
        $this->config->deleteothers = $deleteothers;
        $this->config->handlecollisions = $handlecollisions;
        $this->config->recoverifmultiple = $recoverifmultiple;
        $this->config->maxbytes = get_max_upload_file_size($CFG->maxbytes,$course->maxbytes,$modbytes);
        $this->files = array();
        $this->status = false; 
        $this->course = $course;
        $this->inputname = $inputname;
    }
    
    /** 
     * Gets all entries out of $_FILES and stores them locally in $files
     * Checks each one against get_max_upload_file_size and calls cleanfilename and scans them for viruses etc.
     */
    function preprocess_files() {
        global $CFG;
        foreach ($_FILES as $name => $file) {
            $this->status = true; // only set it to true here so that we can check if this function has been called.
            if (empty($this->inputname) || $name == $this->inputname) { // if we have input name, only process if it matches.
                $file['originalname'] = $file['name']; // do this first for the log.
                $this->files[$name] = $file; // put it in first so we can get uploadlog out in print_upload_log.
                $this->status = $this->validate_file($this->files[$name],empty($this->inputname)); // default to only allowing empty on multiple uploads.
                if (!$this->status && $this->files[$name]['error'] = 0 || $this->files[$name]['error'] == 4 && empty($this->inputname)) {
                    // this shouldn't cause everything to stop.. modules should be responsible for knowing which if any are compulsory.
                    continue; 
                }
                if ($this->status && $CFG->runclamonupload) {
                    $this->status = clam_scan_file($this->files[$name],$this->course);
                }
                if (!$this->status) {
                    if (!$this->config->recoverifmultiple && count($this->files) > 1) {
                        $a->name = $this->files[$name]['originalname'];
                        $a->problem = $this->files[$name]['uploadlog'];
                        notify(get_string('uploadfailednotrecovering','moodle',$a));
                        $this->status = false;
                        return false;
                    }
                    else if (count($this->files) == 1) {
                        notify($this->files[$name]['uploadlog']);
                        $this->status = false;
                        return false;
                    }
                }
                else {
                    $newname = clean_filename($this->files[$name]['name']);
                    if ($newname != $this->files[$name]['name']) {
                        $a->oldname = $this->files[$name]['name'];
                        $a->newname = $newname;
                        $this->files[$name]['uploadlog'] .= get_string('uploadrenamedchars','moodle',$a);
                    }
                    $this->files[$name]['name'] = $newname;
                    $this->files[$name]['clear'] = true; // ok to save.
                }
            }
        }
        $this->status = true;
        return true; // if we've got this far it means that we're recovering so we want status to be ok.
    }

    /**
     * Validates a single file entry from _FILES
     * @param $file - the entry from _FILES to validate
     * @param $allowempty - this is to allow module owners to control which files are compulsory if this function is being called straight from the module.
     * @return true if ok.
     */
    function validate_file(&$file,$allowempty=true) {
        if (empty($file)) {
            return $allowempty; // this shouldn't cause everything to stop.. modules should be responsible for knowing which if any are compulsory.
        }
        if (!is_uploaded_file($file['tmp_name']) || $file['size'] == 0) {
            $file['uploadlog'] .= "\n".$this->get_file_upload_error($file);
            if ($file['error'] == 0 || $file['error'] == 4) {
                return $allowempty;
            }
            return false;
        }
        if ($file['size'] > $this->config->maxbytes) {
            $file['uploadlog'] .= "\n".get_string("uploadedfiletoobig", "moodle", $this->config->maxbytes);
            return false;
        }
        return true;
    }

    /** 
     * Moves all the files to the destination directory.
     * @param $destination - the destination directory.
     * @return status;
     */
    function save_files($destination) {
        global $CFG,$USER;
        
        if (!$this->status) { // preprocess_files hasn't been run
            $this->preprocess_files();
        }
        if ($this->status) {
            if (!(strpos($destination,$CFG->dataroot) === false)) {
                // take it out for giving to make_upload_directory
                $destination = substr($destination,strlen($CFG->dataroot)+1);
            }

            if ($destination{strlen($destination)-1} == "/") { // strip off a trailing / if we have one
                $destination = substr($destination,0,-1);
            }

            if (!make_upload_directory($destination,true)) { //TODO maybe put this function here instead of moodlelib.php now.
                $this->status = false;
                return false;
            }
            
            $destination = $CFG->dataroot.'/'.$destination; // now add it back in so we have a full path

            $exceptions = array(); //need this later if we're deleting other files.

            foreach (array_keys($this->files) as $i) {

                if (!$this->files[$i]['clear']) {
                    // not ok to save
                    continue;
                }

                if ($this->config->handlecollisions) {
                    $this->handle_filename_collision($destination,$this->files[$i]);
                }
                if (move_uploaded_file($this->files[$i]['tmp_name'], $destination.'/'.$this->files[$i]['name'])) {
                    chmod($destination.'/'.$this->files[$i]['name'], $CFG->directorypermissions);
                    $this->files[$i]['fullpath'] = $destination.'/'.$this->files[$i]['name'];
                    $this->files[$i]['uploadlog'] .= "\n".get_string('uploadedfile');
                    $this->files[$i]['saved'] = true;
                    $exceptions[] = $this->files[$i]['name'];
                    // now add it to the log (this is important so we know who to notify if a virus is found later on)
                    clam_log_upload($this->files[$i]['fullpath'],$this->course);
                    $savedsomething=true;
                }
            }
            if ($savedsomething && $this->config->deleteothers) {
                $this->delete_other_files($destination,$exceptions);
            }
        }
        if (!$savedsomething) {
            $this->status = false;
            return false;
        }
        return $this->status;
    }
    
    /**
     * Wrapper function that calls preprocess_files and viruscheck_files and then save_files
     * Modules that require the insert id in the filepath should not use this and call these functions seperately in the required order.
     * @parameter $destination - where to save the uploaded files to.
     */ 
    function process_file_uploads($destination) {
        if ($this->preprocess_files()) {
            return $this->save_files($destination);
        }
        return false;
    }

    /** 
     * Deletes all the files in a given directory except for the files in $exceptions (full paths)
     * @param $destination - the directory to clean up.
     * @param $exceptions - array of full paths of files to KEEP.
     */
    function delete_other_files($destination,$exceptions=null) {
        if ($filestodel = get_directory_list($destination)) {
            foreach ($filestodel as $file) {
                if (!is_array($exceptions) || !in_array($file,$exceptions)) {
                    unlink("$destination/$file");
                    $deletedsomething = true;
                }
            }
        }
        if ($deletedsomething) {
            notify(get_string('uploadoldfilesdeleted'));
        }
    }
    
    /**
     * Handles filename collisions - if the desired filename exists it will rename it according to the pattern in $format
     * @param $destination - destination directory (to check existing files against)
     * @param $file - the current file from $files we're processing.
     * @param $format - the printf style format to rename the file to (defaults to filename_number.extn)
     * @return new filename.
     */
    function handle_filename_collision($destination,&$file,$format='%s_%d.%s') {
        $bits = explode('.',$file['name']);
        // check for collisions and append a nice numberydoo.
        if (file_exists($destination.'/'.$file['name'])) {
            $a->oldname = $file['name'];
            for ($i = 1; true; $i++) {
                $try = sprintf($format,$bits[0],$i,$bits[1]);
                if ($this->check_before_renaming($destination,$try,$file)) {
                    $file['name'] = $try;
                    break;
                }
            }
            $a->newname = $file['name'];
            $file['uploadlog'] .= "\n".get_string('uploadrenamedcollision','moodle',$a);
        }
    }
    
    /**
     * This function checks a potential filename against what's on the filesystem already and what's been saved already.
     */
    function check_before_renaming($destination,$nametocheck,$file) {
        if (!file_exists($destination.'/'.$nametocheck)) {
            return true;
        }
        if ($this->config->deleteothers) {
            foreach ($this->files as $tocheck) {
                // if we're deleting files anyway, it's not THIS file and we care about it and it has the same name and has already been saved..
                if ($file['tmp_name'] != $tocheck['tmp_name'] && $tocheck['clear'] && $nametocheck == $tocheck['name'] && $tocheck['saved']) {
                    $collision = true;
                }
            }
            if (!$collision) {
                return true;
            }
        }
        return false;
    }

    
    function get_file_upload_error(&$file) {
        
        switch ($file['error']) {
        case 0: // UPLOAD_ERR_OK
            if ($file['size'] > 0) {
                $errmessage = get_string('uploadproblem', $file['name']);
            } else {
                $errmessage = get_string('uploadnofilefound'); /// probably a dud file name
            }
            break;
            
        case 1: // UPLOAD_ERR_INI_SIZE
            $errmessage = get_string('uploadserverlimit');
            break;
            
        case 2: // UPLOAD_ERR_FORM_SIZE
            $errmessage = get_string('uploadformlimit');
            break;
            
        case 3: // UPLOAD_ERR_PARTIAL
            $errmessage = get_string('uploadpartialfile');
            break;
            
        case 4: // UPLOAD_ERR_NO_FILE
            $errmessage = get_string('uploadnofilefound');
            break;
            
        default:
            $errmessage = get_string('uploadproblem', $file['name']);
        }
        return $errmessage;
    }
    
    /**
     * prints a log of everything that happened (of interest) to each file in _FILES
     * @param $return - optional, defaults to false (log is echoed)
     */
    function print_upload_log($return=false) {
        foreach (array_keys($this->files) as $i => $key) {
            $str .= '<b>'.get_string('uploadfilelog','moodle',$i+1).' '
                .((!empty($this->files[$key]['originalname'])) ? '('.$this->files[$key]['originalname'].')' : '')
                .'</b> :'.nl2br($this->files[$key]['uploadlog']).'<br />';
        }
        if ($return) {
            return $str;
        }
        echo $str;
    }

    /**
     * If we're only handling one file (if inputname was given in the constructor) this will return the (possibly changed) filename of the file.
     */
    function get_new_filename() {
        if (!empty($this->inputname) && count($this->files) == 1) {
            return $this->files[$this->inputname]['name'];
        }
        return false;
    }

    /** 
     * If we're only handling one file (if inputname was given in the constructor) this will return the ORIGINAL filename of the file.
     */
    function get_original_filename() {
        if (!empty($this->inputname) && count($this->files) == 1) {
            return $this->files[$this->inputname]['originalname'];
        }
        return false;
    }
}

/**************************************************************************************
THESE FUNCTIONS ARE OUTSIDE THE CLASS BECAUSE THEY NEED TO BE CALLED FROM OTHER PLACES.
FOR EXAMPLE CLAM_HANDLE_INFECTED_FILE AND CLAM_REPLACE_INFECTED_FILE USED FROM CRON
UPLOAD_PRINT_FORM_FRAGMENT DOESN'T REALLY BELONG IN THE CLASS BUT CERTAINLY IN THIS FILE
***************************************************************************************/


/**
 * This function prints out a number of upload form elements
 * @param $numfiles - the number of elements required (optional, defaults to 1)
 * @param $names - array of element names to use (optional, defaults to FILE_n)
 * @param $descriptions - array of strings to be printed out before each file bit.
 * @param $uselabels - whether to output text fields for file descriptions or not (optional, defaults to false)
 * @param $labelnames - array of element names to use for labels (optional, defaults to LABEL_n)
 * @param $coursebytes 
 * @param $modbytes - these last two are used to calculate upload max size ( using get_max_upload_file_size)
 * @param $return - whether to return the string (defaults to false - string is echoed)
 */ 
function upload_print_form_fragment($numfiles=1,$names=null,$descriptions=null,$uselabels=false,$labelnames=null,$coursebytes=0,$modbytes=0,$return=false) {
    global $CFG;
    $maxbytes = get_max_upload_file_size($CFG->maxbytes,$coursebytes,$modbytes);
    $str = '<input type="hidden" name="MAX_FILE_SIZE" value="'.$maxbytes.'" />'."\n";
    for ($i = 0; $i < $numfiles; $i++) {
        if (is_array($descriptions) && !empty($descriptions[$i])) {
            $str .= '<b>'.$descriptions[$i].'</b><br />';
        }
        $str .= '<input type="file" size="50" name="'.((is_array($names) && !empty($names[$i])) ? $names[$i] : 'FILE_'.$i).'" /><br />'."\n";
        if ($uselabels) {
            $str .= get_string('uploadlabel').' <input type="text" size="50" name="'
                .((is_array($labelnames) && !empty($labelnames[$i])) ? $labelnames[$i] : 'LABEL_'.$i)
                .'" /><br /><br />'."\n";
        }
    }
    if ($return) {
        return $str;
    }
    else {
        echo $str;
    }
}


/**
 * Deals with an infected file - either moves it to a quarantinedir 
 * (specified in CFG->quarantinedir) or deletes it.
 * If moving it fails, it deletes it.
 * @param file full path to the file
 * @param userid - if not used, defaults to $USER->id (there in case called from cron)
 * @param basiconly - admin level reporting or user level reporting.
 * @return a string of what it did.
 */
function clam_handle_infected_file($file,$userid=0,$basiconly=false) {
    
    global $CFG,$USER;
    if ($USER && !$userid) {
        $userid = $USER->id;
    }
    $delete = true;
    if (file_exists($CFG->quarantinedir) && is_dir($CFG->quarantinedir) && is_writable($CFG->quarantinedir)) {
        $now = date('YmdHis');
        if (rename($file,$CFG->quarantinedir.'/'.$now.'-user-'.$userid.'-infected')) { 
            $delete = false;
            if ($basiconly) {
                $notice .= "\n".get_string('clammovedfilebasic');
            }
            else {
                $notice .= "\n".get_string('clammovedfile','moodle',$CFG->quarantinedir.'/'.$now.'-user-'.$userid.'-infected');
            }
        }
        else {
            if ($basiconly) {
                $notice .= "\n".get_string('clamdeletedfile');
            }
            else {
                $notice .= "\n".get_string('clamquarantinedirfailed','moodle',$CFG->quarantinedir);
            }
        }
    }
    else {
        if ($basiconly) {
            $notice .= "\n".get_string('clamdeletedfile');
        }
        else {
            $notice .= "\n".get_string('clamquarantinedirfailed','moodle',$CFG->quarantinedir);
        }
    }
    if ($delete) {
        if (unlink($file)) {
            $notice .= "\n".get_string('clamdeletedfile');
        }
        else {
            if ($basiconly) {
                // still tell the user the file has been deleted. this is only for admins.
                $notice .= "\n".get_string('clamdeletedfile');
            }
            else {
                $notice .= "\n".get_string('clamdeletedfilefailed');
            }
        }
    }
    return $notice;
}

/**
 * Replaces the given file with a string to notify that the original file had a virus.
 * This is to avoid missing files but could result in the wrong content-type.
 * @param file - full path to the file.
 */
function clam_replace_infected_file($file) {
    $newcontents = get_string('virusplaceholder');
    if (!$f = fopen($file,'w')) {
        return false;
    }
    if (!fwrite($f,$newcontents)) {
        return false;
    }
    return true;
}


/**
 * If $CFG->runclamonupload is set, we scan a given file. (called from preprocess_files)
 * This function will add on a uploadlog index in $file.
 * @param $file - the file to scan from $files. or an absolute path to a file.
 * @return 1 if good, 0 if something goes wrong (opposite from actual error code from clam)
 */ 
function clam_scan_file(&$file,$course) {
    global $CFG,$USER;

    if (is_array($file) && is_uploaded_file($file['tmp_name'])) { // it's from $_FILES
        $appendlog = true; 
        $fullpath = $file['tmp_name'];
    }
    else if (file_exists($file)) { // it's a path to somewhere on the filesystem!
        $fullpath = $file;
    }
    else {
        return false; // erm, what is this supposed to be then, huh?
    }

    if (!$CFG->pathtoclam || !file_exists($CFG->pathtoclam) || !is_executable($CFG->pathtoclam)) {
        $newreturn = 1;
        $notice = get_string('clamlost','moodle',$CFG->pathtoclam);
        if ($CFG->clamfailureonupload == 'actlikevirus') {
            $notice .= "\n".get_string('clamlostandactinglikevirus');
            $notice .= "\n".clam_handle_infected_file($fullpath);
            $newreturn = false; 
        }
        clam_mail_admins($notice);
        return $newreturn; // return 1 if we're allowing clam failures
    }
    
    $cmd = $CFG->pathtoclam.' '.$fullpath." 2>&1";
    
    // before we do anything we need to change perms so that clamscan can read the file (clamdscan won't work otherwise)
    chmod($fullpath,0644);
    
    exec($cmd,$output,$return);
    
    
    switch ($return) {
    case 0: // glee! we're ok.
        return 1; // translate clam return code into reasonable return code consistent with everything else.
    case 1:  // bad wicked evil, we have a virus.
        if (!empty($course)) {
            $info->course = $course->fullname;
        }
        else {
            $info->course = 'No course';
        }
        $info->user = $USER->firstname.' '.$USER->lastname;
        $notice = get_string('virusfound','moodle',$info);
        $notice .= "\n\n".implode("\n",$output);
        $notice .= "\n\n".clam_handle_infected_file($fullpath); 
        clam_mail_admins($notice);
        if ($appendlog) {
            $info->filename = $file['originalname'];
            $file['uploadlog'] .= "\n".get_string('virusfounduser','moodle',$info);
            $file['virus'] = 1;
        }
        return false; // in this case, 0 means bad.
    default: 
        // error - clam failed to run or something went wrong
        $notice .= get_string('clamfailed','moodle',get_clam_error_code($return));
        $notice .= "\n\n".implode("\n",$output);
        $newreturn = true;
        if ($CFG->clamfailureonupload == 'actlikevirus') {
            $notice .= "\n".clam_handle_infected_file($fullpath);
            $newreturn = false;
        }
        clam_mail_admins($notice);
        if ($appendlog) {
            $file['uploadlog'] .= "\n".get_string('clambroken');
            $file['clam'] = 1;
        }
        return $newreturn; // return 1 if we're allowing failures.
    }
}

/**
 * emails admins about a clam outcome
 * @param notice - the body of the email.
 */
function clam_mail_admins($notice) {
    
    $site = get_site();
        
    $subject = get_string('clamemailsubject','moodle',$site->fullname);
    $admins = get_admins();
    foreach ($admins as $admin) {
        email_to_user($admin,get_admin(),$subject,$notice);
    }
}


function get_clam_error_code($returncode) {
    $returncodes = array();
    $returncodes[0] = 'No virus found.';
    $returncodes[1] = 'Virus(es) found.';
    $returncodes[2] = ' An error occured'; // specific to clamdscan
    // all after here are specific to clamscan
    $returncodes[40] = 'Unknown option passed.';
    $returncodes[50] = 'Database initialization error.';
    $returncodes[52] = 'Not supported file type.';
    $returncodes[53] = 'Can\'t open directory.';
    $returncodes[54] = 'Can\'t open file. (ofm)';
    $returncodes[55] = 'Error reading file. (ofm)';
    $returncodes[56] = 'Can\'t stat input file / directory.';
    $returncodes[57] = 'Can\'t get absolute path name of current working directory.';
    $returncodes[58] = 'I/O error, please check your filesystem.';
    $returncodes[59] = 'Can\'t get information about current user from /etc/passwd.';
    $returncodes[60] = 'Can\'t get information about user \'clamav\' (default name) from /etc/passwd.';
    $returncodes[61] = 'Can\'t fork.'; 
    $returncodes[63] = 'Can\'t create temporary files/directories (check permissions).';
    $returncodes[64] = 'Can\'t write to temporary directory (please specify another one).';
    $returncodes[70] = 'Can\'t allocate and clear memory (calloc).';
    $returncodes[71] = 'Can\'t allocate memory (malloc).';
    if ($returncodes[$returncode])
       return $returncodes[$returncode];
    return get_string('clamunknownerror');

}

/**
 * adds a file upload to the log table so that clam can resolve the filename to the user later if necessary
 */
function clam_log_upload($newfilepath,$course=null) {
    global $CFG,$USER;
    // get rid of any double // that might have appeared
    $newfilepath = preg_replace('/\/\//','/',$newfilepath);
    if (strpos($newfilepath,$CFG->dataroot) === false) {
        $newfilepath = $CFG->dataroot.'/'.$newfilepath;
    }
    $CFG->debug=10;
    $courseid = 0;
    if ($course) {
        $courseid = $course->id;
    }
    add_to_log($courseid,"upload","upload","",$newfilepath);
}

/**
 * some of the modules allow moving attachments (glossary), in which case we need to hunt down an original log and change the path.
 */
function clam_change_log($oldpath,$newpath) {
    global $CFG;
    $sql = "UPDATE {$CFG->prefix}log SET info = '$newpath' WHERE module = 'upload' AND info = '$oldpath'";
    execute_sql($sql);
}
?>