file.php

   1 <?php // $Id$
   2       // This script fetches files from the dataroot directory
   3       // Syntax:      file.php/courseid/dir/dir/dir/filename.ext
   4       //              file.php/courseid/dir/dir/dir/filename.ext?forcedownload=1 (download instead of inline)
   5       //              file.php/courseid/dir (returns index.html from dir)
   6       // Workaround:  file.php?file=/courseid/dir/dir/dir/filename.ext
   7       // Test:        file.php/testslasharguments
   8
   9     require_once('config.php');
  10     require_once('lib/filelib.php');
  11
  12     if (empty($CFG->filelifetime)) {
  13         $lifetime = 86400;     // Seconds for files to remain in caches
  14     } else {
  15         $lifetime = $CFG->filelifetime;
  16     }
  17
  18
  19     $relativepath = get_file_argument('file.php');
  20     $forcedownload = optional_param('forcedownload', 0, PARAM_BOOL);
  21
  22     // relative path must start with '/', because of backup/restore!!!
  23     if (!$relativepath) {
  24         error('No valid arguments supplied or incorrect server configuration');
  25     } else if ($relativepath{0} != '/') {
  26         error('No valid arguments supplied, path does not start with slash!');
  27     }
  28
  29     $pathname = $CFG->dataroot.$relativepath;
  30
  31     // extract relative path components
  32     $args = explode('/', trim($relativepath, '/'));
  33     if (count($args) == 0) { // always at least courseid, may search for index.html in course root
  34         error('No valid arguments supplied');
  35     }
  36
  37     // security: limit access to existing course subdirectories
  38     // note: course ID must be specified
  39     // note: the lang field is needed for the course language switching hack in weblib.php
  40     if (!$course = get_record_sql("SELECT id, lang FROM {$CFG->prefix}course WHERE id='".(int)$args[0]."'")) {
  41         error('Invalid course ID');
  42     }
  43
  44     // security: prevent access to "000" or "1 something" directories
  45     if ($args[0] != $course->id) {
  46         error('Invalid course ID');
  47     }
  48
  49     // security: login to course if necessary
  50     if ($course->id != SITEID) {
  51         require_login($course->id);
  52     } else if ($CFG->forcelogin) {
  53         require_login();
  54     }
  55
  56     // security: only editing teachers can access backups
  57     if ((count($args) >= 2) and (strtolower($args[1]) == 'backupdata')) {
  58         if (!isteacheredit($course->id)) {
  59             error('Access not allowed');
  60         } else {
  61             $lifetime = 0; //disable browser caching for backups
  62         }
  63     }
  64
  65     if (is_dir($pathname)) {
  66         if (file_exists($pathname.'/index.html')) {
  67             $pathname = rtrim($pathname, '/').'/index.html';
  68             $args[] = 'index.html';
  69         } else if (file_exists($pathname.'/index.htm')) {
  70             $pathname = rtrim($pathname, '/').'/index.htm';
  71             $args[] = 'index.htm';
  72         } else if (file_exists($pathname.'/Default.htm')) {
  73             $pathname = rtrim($pathname, '/').'/Default.htm';
  74             $args[] = 'Default.htm';
  75         } else {
  76             // security: do not return directory node!
  77             not_found($course->id);
  78         }
  79     }
  80
  81     // security: teachers can view all assignments, students only their own
  82     if ((count($args) >= 3)
  83         and (strtolower($args[1]) == 'moddata')
  84         and (strtolower($args[2]) == 'assignment')) {
  85
  86         $lifetime = 0;  // do not cache assignments, students may reupload them
  87         if ((!isteacher($course->id)) && (count($args) != 6 || $args[4] != $USER->id)) {
  88            error('Access not allowed');
  89         }
  90     }
  91
  92     // security: force download of all attachments submitted by students
  93     if ((count($args) >= 3)
  94         and (strtolower($args[1]) == 'moddata')
  95         and ((strtolower($args[2]) == 'forum')
  96             or (strtolower($args[2]) == 'assignment')
  97             or (strtolower($args[2]) == 'data')
  98             or (strtolower($args[2]) == 'glossary')
  99             or (strtolower($args[2]) == 'wiki')
 100             or (strtolower($args[2]) == 'exercise')
 101             or (strtolower($args[2]) == 'workshop')
 102             )) {
 103         $forcedownload  = 1; // force download of all attachments
 104     }
 105
 106     // security: some protection of hidden resource files
 107     // warning: it may break backwards compatibility
 108     if ((!empty($CFG->preventaccesstohiddenfiles))
 109         and (count($args) >= 2)
 110         and (!isteacher($course->id))) {
 111
 112         $reference = ltrim($relativepath, "/{$args[0]}/");
 113
 114         $sql = "SELECT COUNT(r.id) " .
 115                  "FROM {$CFG->prefix}resource r, " .
 116                       "{$CFG->prefix}course_modules cm, " .
 117                       "{$CFG->prefix}modules m " .
 118                  "WHERE r.course    = '{$course->id}' " .
 119                    "AND m.name      = 'resource' " .
 120                    "AND cm.module   = m.id " .
 121                    "AND cm.instance = r.id " .
 122                    "AND cm.visible  = 0 " .
 123                    "AND r.type      = 'file' " .
 124                    "AND r.reference = '{$reference}'";
 125         if (count_records_sql($sql)) {
 126            error('Access not allowed');
 127         }
 128     }
 129
 130     // check that file exists
 131     if (!file_exists($pathname)) {
 132         not_found($course->id);
 133     }
 134
 135     // extra security: keep symbolic links inside dataroot/courseid if required
 136     /*if (!empty($CFG->checksymlinks)) {
 137         $realpath = realpath($pathname);
 138         $realdataroot = realpath($CFG->dataroot.'/'.$course->id);
 139         if (strpos($realpath, $realdataroot) !== 0) {
 140             not_found($course->id);
 141         }
 142     }*/
 143
 144     // ========================================
 145     // finally send the file
 146     // ========================================
 147     session_write_close(); // unlock session during fileserving
 148     $filename = $args[count($args)-1];
 149     send_file($pathname, $filename, $lifetime, $CFG->filteruploadedfiles, false, $forcedownload);
 150
 151     function not_found($courseid) {
 152         global $CFG;
 153         header('HTTP/1.0 404 not found');
 154         error(get_string('filenotfound', 'error'), $CFG->wwwroot.'/course/view.php?id='.$courseid); //this is not displayed on IIS??
 155     }
 156 ?>