.
/**
* 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;
$error_message1 = "Your system is not configured to run mimeTeX. You need to download the appropriate
"
."executable for you ".PHP_OS." platform from "
."http://moodle.org/download/mimetex/, or obtain the C source
"
."from "
."http://www.forkosh.com/mimetex.zip, compile it and "
."put the executable into your
moodle/filter/tex/ directory.";
$error_message2 = "Custom mimetex is not executable!
";
if ((PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows")) {
return "$CFG->dirroot/filter/tex/mimetex.exe";
}
if ($pathmimetex = get_config('filter_tex', 'pathmimetex')) {
if (is_executable($pathmimetex)) {
return $pathmimetex;
} else {
print_error('mimetexnotexecutable', 'error');
}
}
$custom_commandpath = "$CFG->dirroot/filter/tex/mimetex";
if (file_exists($custom_commandpath)) {
if (is_executable($custom_commandpath)) {
return $custom_commandpath;
} else {
print_error('mimetexnotexecutable', 'error');
}
}
switch (PHP_OS) {
case "Linux": return "$CFG->dirroot/filter/tex/mimetex.linux";
case "Darwin": return "$CFG->dirroot/filter/tex/mimetex.darwin";
case "FreeBSD": return "$CFG->dirroot/filter/tex/mimetex.freebsd";
}
print_error('mimetexisnotexist', 'error');
}
function filter_tex_sanitize_formula($texexp) {
/// Check $texexp against blacklist (whitelisting could be more complete but also harder to maintain)
$tex_blacklist = array(
'include','command','loop','repeat','open','toks','output',
'input','catcode','name','^^',
'\def','\edef','\gdef','\xdef',
'\every','\errhelp','\errorstopmode','\scrollmode','\nonstopmode',
'\batchmode','\read','\write','csname','\newhelp','\uppercase',
'\lowercase','\relax','\aftergroup',
'\afterassignment','\expandafter','\noexpand','\special',
'\let', '\futurelet','\else','\fi','\chardef','\makeatletter','\afterground',
'\noexpand','\line','\mathcode','\item','\section','\mbox','\declarerobustcommand'
);
return str_ireplace($tex_blacklist, 'forbiddenkeyword', $texexp);
}
function filter_tex_get_cmd($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');
}
}