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See Release Notes

  • Bug fixes for general core bugs in 3.11.x will end 14 Nov 2022 (12 months plus 6 months extension).
  • Bug fixes for security issues in 3.11.x will end 13 Nov 2023 (18 months plus 12 months extension).
  • PHP version: minimum PHP 7.3.0 Note: minimum PHP version has increased since Moodle 3.10. PHP 7.4.x is supported too.
/filter/tex/ -> lib.php (source)
<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle 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.
//
// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * TeX filter library functions.
 *
 * @package    filter
 * @subpackage tex
 * @copyright  2004 Zbigniew Fiedorowicz fiedorow@math.ohio-state.edu
 *             Originally based on code provided by Bruno Vernier bruno@vsbeducation.ca
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

defined('MOODLE_INTERNAL') || die();

function filter_tex_get_executable($debug=false) {
    global $CFG;

    if ((PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows")) {
        return "$CFG->dirroot/filter/tex/mimetex.exe";
    }

    if ($pathmimetex = get_config('filter_tex', 'pathmimetex')) {
        if (is_executable($pathmimetex)) {
            return $pathmimetex;
        } else {
< print_error('mimetexnotexecutable', 'error');
> throw new \moodle_exception('mimetexnotexecutable', 'error');
} } $custom_commandpath = "$CFG->dirroot/filter/tex/mimetex"; if (file_exists($custom_commandpath)) { if (is_executable($custom_commandpath)) { return $custom_commandpath; } else {
< print_error('mimetexnotexecutable', 'error');
> throw new \moodle_exception('mimetexnotexecutable', 'error');
} } switch (PHP_OS) { case "Darwin": return "$CFG->dirroot/filter/tex/mimetex.darwin"; case "FreeBSD": return "$CFG->dirroot/filter/tex/mimetex.freebsd"; case "Linux": if (php_uname('m') == 'aarch64') { return "$CFG->dirroot/filter/tex/mimetex.linux.aarch64"; } return "$CFG->dirroot/filter/tex/mimetex.linux"; }
< print_error('mimetexisnotexist', 'error');
> throw new \moodle_exception('mimetexisnotexist', 'error');
} /** * Check the formula expression against the list of denied keywords. * * List of allowed could be more complete but also harder to maintain. * * @param string $texexp Formula expression to check. * @return string Formula expression with denied keywords replaced with 'forbiddenkeyword'. */ function filter_tex_sanitize_formula(string $texexp): string { $denylist = [ 'include', 'command', 'loop', 'repeat', 'open', 'toks', 'output', 'input', 'catcode', 'name', '^^', '\def', '\edef', '\gdef', '\xdef', '\every', '\errhelp', '\errorstopmode', '\scrollmode', '\nonstopmode', '\batchmode', '\read', '\write', 'csname', '\newhelp', '\uppercase', '\lowercase', '\relax', '\aftergroup', '\afterassignment', '\expandafter', '\noexpand', '\special', '\let', '\futurelet', '\else', '\fi', '\chardef', '\makeatletter', '\afterground', '\noexpand', '\line', '\mathcode', '\item', '\section', '\mbox', '\declarerobustcommand', '\ExplSyntaxOn', ]; $allowlist = ['inputenc']; // Prepare the denylist for regular expression. $denylist = array_map(function($value){ return '/' . preg_quote($value, '/') . '/i'; }, $denylist); // Prepare the allowlist for regular expression. $allowlist = array_map(function($value){ return '/\bforbiddenkeyword_(' . preg_quote($value, '/') . ')\b/i'; }, $allowlist); // First, mangle all denied words. $texexp = preg_replace_callback($denylist, function($matches) { return 'forbiddenkeyword_' . $matches[0]; }, $texexp ); // Then, change back the allowed words. $texexp = preg_replace_callback($allowlist, function($matches) { return $matches[1]; }, $texexp ); return $texexp; } function filter_tex_get_cmd($pathname, $texexp) { $texexp = filter_tex_sanitize_formula($texexp); $texexp = escapeshellarg($texexp); $executable = filter_tex_get_executable(false); if ((PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows")) { $executable = str_replace(' ', '^ ', $executable); return "$executable ++ -e \"$pathname\" -- $texexp"; } else { return "\"$executable\" -e \"$pathname\" -- $texexp"; } } /** * Purge all caches when settings changed. */ function filter_tex_updatedcallback($name) { global $CFG, $DB; reset_text_filters_cache(); if (file_exists("$CFG->dataroot/filter/tex")) { remove_dir("$CFG->dataroot/filter/tex"); } if (file_exists("$CFG->dataroot/filter/algebra")) { remove_dir("$CFG->dataroot/filter/algebra"); } if (file_exists("$CFG->tempdir/latex")) { remove_dir("$CFG->tempdir/latex"); } $DB->delete_records('cache_filters', array('filter'=>'tex')); $DB->delete_records('cache_filters', array('filter'=>'algebra')); $pathlatex = get_config('filter_tex', 'pathlatex'); if ($pathlatex === false) { // detailed settings not present yet return; } $pathlatex = trim($pathlatex, " '\""); $pathdvips = trim(get_config('filter_tex', 'pathdvips'), " '\""); $pathconvert = trim(get_config('filter_tex', 'pathconvert'), " '\""); $pathdvisvgm = trim(get_config('filter_tex', 'pathdvisvgm'), " '\""); $supportedformats = array('gif'); if ((is_file($pathlatex) && is_executable($pathlatex)) && (is_file($pathdvips) && is_executable($pathdvips))) { if (is_file($pathconvert) && is_executable($pathconvert)) { $supportedformats[] = 'png'; } if (is_file($pathdvisvgm) && is_executable($pathdvisvgm)) { $supportedformats[] = 'svg'; } } if (!in_array(get_config('filter_tex', 'convertformat'), $supportedformats)) { set_config('convertformat', array_pop($supportedformats), 'filter_tex'); } }