1: package Apache::run;
2: #
3: # $Id: run.pm,v 1.63 2014/12/15 17:45:16 raeburn Exp $
4: #
5: # Copyright Michigan State University Board of Trustees
6: #
7: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
8: #
9: # LON-CAPA is free software; you can redistribute it and/or modify
10: # it under the terms of the GNU General Public License as published by
11: # the Free Software Foundation; either version 2 of the License, or
12: # (at your option) any later version.
13: #
14: # LON-CAPA is distributed in the hope that it will be useful,
15: # but WITHOUT ANY WARRANTY; without even the implied warranty of
16: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17: # GNU General Public License for more details.
18: #
19: # You should have received a copy of the GNU General Public License
20: # along with LON-CAPA; if not, write to the Free Software
21: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22: #
23: # /home/httpd/html/adm/gpl.txt
24: #
25: # http://www.lon-capa.org/
26: #
27:
28: use HTML::Entities;
29: use Apache::lonlocal;
30:
31: $Apache::run::EVALUATE_STRING=<<'ENDEVALUATE';
32: my %_LONCAPA_INTERNAL_oldexpressions=();
33: while (!$_LONCAPA_INTERNAL_oldexpressions{$_}) {
34: $_LONCAPA_INTERNAL_oldexpressions{$_}=1;
35: $_ =~s/ # $1 will be the variable reference or subroutine name
36: ((?:\$|\&) #look for a starting $ or &
37: (?:[\#|\$]* #support $$ or $#$ etc.
38: [A-Za-z][\w]*| # get variable name
39: \{[A-Za-z][\w]*\})) # for ${a}
40: # $2 is 0 or more array dereferences []
41: # or hash dereferences {}
42: # the ^$ and ^& is because we do this iteratively
43: # $a[$c] becomes $a[3] which then evaluates
44: ([\[\{][^\$\&\]\}]+[\]\}])*?
45: # $3 is the list of arguments
46: (\([^\$\&\)]+\))*?
47: # only match the above if there is not { [ ( coming up
48: # Why? (I.e. this fails &a(1)[2]
49: (?=[^\[\{\(]|$)/
50: my ($__LC__a,$__LC__b,$__LC__c)=($1,$2,$3);
51: my $__LC__prefix;
52: my $__LC__result;
53: while (1) {
54: if ($__LC__a =~ m-^&(theta|pi|rho)$-) { last; }
55: {
56: use strict;
57: no strict "vars";
58: if (eval(defined(eval($__LC__a.$__LC__b)))) {
59: $__LC__result= $__LC__prefix.eval($__LC__a.$__LC__b.$__LC__c);
60: last;
61: }
62: }
63: $__LC__prefix.=substr($__LC__a,0,1,"");
64: if ($__LC__a!~m-^(\$|&|\#)-) { last; }
65: }
66: if (!defined($__LC__result)) {
67: $__LC__result=$__LC__prefix.$__LC__a.$__LC__b.$__LC__c;
68: }
69: $__LC__result;
70: /sexg;
71: if (scalar(values(%_LONCAPA_INTERNAL_oldexpressions))>10) {last;}
72: }
73: ENDEVALUATE
74:
75: sub evaluate {
76: my ($expression,$safeeval,$decls) = @_;
77: unless (defined($expression)) { return ''; }
78: if ($Apache::lonxml::evaluate < 1) { return $expression; }
79: my $result = '';
80: $@='';
81: $Apache::run::timeout=0;
82: local $main::SIG{'ALRM'} = sub {
83: $Apache::run::timeout=1;
84: die("timeout");
85: };
86: my $innererror;
87: eval {
88: &Apache::lonxml::start_alarm();
89: $safeeval->reval('{'.$decls.';$_=<<\'EXPRESSION\';'."\n".$expression.
90: "\n".'EXPRESSION'."\n".$EVALUATE_STRING.'}');
91: $innererror=$@;
92: &Apache::lonxml::end_alarm();
93: };
94: my $error=$@;
95: if ($error eq '' && $innererror eq '' && !$Apache::run::timeout) {
96: $result = $safeeval->reval('return $_;');
97: chomp $result;
98: } else {
99: if ($Apache::run::timeout) {
100: $error =
101: &mt('Code ran too long. It ran for more than [_1] seconds.',
102: $Apache::lonnet::perlvar{'lonScriptTimeout'});
103: }
104: &Apache::lonxml::error(
105: &mt('Substitution on [_1] with [_2] caused:',
106: '<pre>'. &HTML::Entities::encode($expression,'<>&"').'</pre>',
107: '<pre>'.&HTML::Entities::encode($decls,'<>&"').'</pre>')
108: .'<br />'
109: .'<pre>'.&HTML::Entities::encode($error,'<>&"').' '
110: .&HTML::Entities::encode($innererror,'<>&"').'</pre>');
111: }
112: return $result;
113: }
114:
115: sub run {
116: my ($code,$safeeval,$hideerrors) = @_;
117: my @result;
118: $@='';
119: $Apache::run::timeout=0;
120: local $main::SIG{'ALRM'} = sub {
121: $Apache::run::timeout=1;
122: die("timeout");
123: };
124: my $innererror;
125: eval {
126: &Apache::lonxml::start_alarm();
127: @result=$safeeval->reval($code);
128: $innererror=$@;
129: &Apache::lonxml::end_alarm();
130: };
131: my $error=$@;
132: if (($Apache::run::timeout || $error ne '' || $innererror ne '') && !$hideerrors) {
133: if ($Apache::run::timeout) {
134: $error = &mt('Code ran too long. It ran for more than [_1] seconds.',
135: $Apache::lonnet::perlvar{'lonScriptTimeout'});
136: }
137: $code=&HTML::Entities::encode($code,'<>&"');
138: if ($innererror=~/line (\d+)/) {
139: my $linenumber=$1;
140: my @code=split("\n",$code);
141: if ($linenumber < scalar(@code)) {
142: $code[$linenumber-1]=
143: '<span style="color:red;font-weight:bold;">'.
144: $code[$linenumber-1].'</span>';
145: }
146: $code=join("\n",@code);
147: }
148: &Apache::lonxml::error(
149: '<pre>'.&HTML::Entities::encode($error,'<>&"').' '.
150: &HTML::Entities::encode($innererror,'<>&"').
151: '</pre>'
152: .&mt('This occurred while running: [_1]',
153: '<pre>'.$code.'</pre>'));
154: }
155: if ( $#result < '1') {
156: return $result[0];
157: } else {
158: &Apache::lonxml::debug("<b>Got lots results</b>:$#result:");
159: return (@result);
160: }
161: }
162:
163: sub dump {
164: my ($target,$safeeval)=@_;
165: my $dump='';
166: foreach my $symname (sort(keys(%{$safeeval->varglob('main::')}))) {
167: if (($symname!~ /^(INC|SIG)/) && ($symname!~/\027/) &&
168: ($symname!~/^\_/) && ($symname!~/\:$/)) {
169: my $line;
170: if ($safeeval->reval('defined($'.$symname.')')) {
171: if ($symname =~ /^\w/) {
172: $line.='$'.$symname.'='.$safeeval->reval('$'.$symname)."\n";
173: }
174: }
175: if ($safeeval->reval('@'.$symname)) {
176: $line.='@'.$symname.'=('.
177: $safeeval->reval('join(",",@'.$symname.')').")"."\n";
178: }
179: if ($safeeval->reval('%'.$symname)) {
180: $line.='%'.$symname.'=(';
181: $line.=$safeeval->reval('join(",",map { $_."=>".$'.
182: $symname.'{$_} } sort(keys(%'.
183: $symname.')))').")"."\n";
184: }
185: if ($line ne '') {
186: $line=&HTML::Entities::encode($line,'<>&"');
187: $line=~s|\n|<br />|g;
188: $dump.=$line;
189: }
190: }
191: }
192: $dump.='';
193: return $dump;
194: }
195:
196: 1;
197: __END__;
198:
199: =pod
200:
201: =head1 NAME
202:
203: Apache::run.pm
204:
205: =head1 SYNOPSIS
206:
207: Used to prevent poorly written problems from
208: causing lingering after effects
209:
210: This is part of the LearningOnline Network with CAPA project
211: described at http://www.lon-capa.org.
212:
213:
214: =head1 NOTABLE SUBROUTINES
215:
216: =over
217:
218: =item run(), dump(), evaluate()
219:
220: =back
221:
222: =cut
223:
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