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1 | package CGI::Carp; |
2 | ||
3 | =head1 NAME | |
4 | ||
5 | B<CGI::Carp> - CGI routines for writing to the HTTPD (or other) error log | |
6 | ||
7 | =head1 SYNOPSIS | |
8 | ||
9 | use CGI::Carp; | |
10 | ||
11 | croak "We're outta here!"; | |
12 | confess "It was my fault: $!"; | |
13 | carp "It was your fault!"; | |
14 | warn "I'm confused"; | |
15 | die "I'm dying.\n"; | |
16 | ||
17 | use CGI::Carp qw(cluck); | |
18 | cluck "I wouldn't do that if I were you"; | |
19 | ||
20 | use CGI::Carp qw(fatalsToBrowser); | |
21 | die "Fatal error messages are now sent to browser"; | |
22 | ||
23 | =head1 DESCRIPTION | |
24 | ||
25 | CGI scripts have a nasty habit of leaving warning messages in the error | |
26 | logs that are neither time stamped nor fully identified. Tracking down | |
27 | the script that caused the error is a pain. This fixes that. Replace | |
28 | the usual | |
29 | ||
30 | use Carp; | |
31 | ||
32 | with | |
33 | ||
34 | use CGI::Carp | |
35 | ||
36 | And the standard warn(), die (), croak(), confess() and carp() calls | |
37 | will automagically be replaced with functions that write out nicely | |
38 | time-stamped messages to the HTTP server error log. | |
39 | ||
40 | For example: | |
41 | ||
42 | [Fri Nov 17 21:40:43 1995] test.pl: I'm confused at test.pl line 3. | |
43 | [Fri Nov 17 21:40:43 1995] test.pl: Got an error message: Permission denied. | |
44 | [Fri Nov 17 21:40:43 1995] test.pl: I'm dying. | |
45 | ||
46 | =head1 REDIRECTING ERROR MESSAGES | |
47 | ||
48 | By default, error messages are sent to STDERR. Most HTTPD servers | |
49 | direct STDERR to the server's error log. Some applications may wish | |
50 | to keep private error logs, distinct from the server's error log, or | |
51 | they may wish to direct error messages to STDOUT so that the browser | |
52 | will receive them. | |
53 | ||
54 | The C<carpout()> function is provided for this purpose. Since | |
55 | carpout() is not exported by default, you must import it explicitly by | |
56 | saying | |
57 | ||
58 | use CGI::Carp qw(carpout); | |
59 | ||
60 | The carpout() function requires one argument, which should be a | |
61 | reference to an open filehandle for writing errors. It should be | |
62 | called in a C<BEGIN> block at the top of the CGI application so that | |
63 | compiler errors will be caught. Example: | |
64 | ||
65 | BEGIN { | |
66 | use CGI::Carp qw(carpout); | |
67 | open(LOG, ">>/usr/local/cgi-logs/mycgi-log") or | |
68 | die("Unable to open mycgi-log: $!\n"); | |
69 | carpout(LOG); | |
70 | } | |
71 | ||
72 | carpout() does not handle file locking on the log for you at this point. | |
73 | ||
74 | The real STDERR is not closed -- it is moved to CGI::Carp::SAVEERR. Some | |
75 | servers, when dealing with CGI scripts, close their connection to the | |
76 | browser when the script closes STDOUT and STDERR. CGI::Carp::SAVEERR is there to | |
77 | prevent this from happening prematurely. | |
78 | ||
79 | You can pass filehandles to carpout() in a variety of ways. The "correct" | |
80 | way according to Tom Christiansen is to pass a reference to a filehandle | |
81 | GLOB: | |
82 | ||
83 | carpout(\*LOG); | |
84 | ||
85 | This looks weird to mere mortals however, so the following syntaxes are | |
86 | accepted as well: | |
87 | ||
88 | carpout(LOG); | |
89 | carpout(main::LOG); | |
90 | carpout(main'LOG); | |
91 | carpout(\LOG); | |
92 | carpout(\'main::LOG'); | |
93 | ||
94 | ... and so on | |
95 | ||
96 | FileHandle and other objects work as well. | |
97 | ||
98 | Use of carpout() is not great for performance, so it is recommended | |
99 | for debugging purposes or for moderate-use applications. A future | |
100 | version of this module may delay redirecting STDERR until one of the | |
101 | CGI::Carp methods is called to prevent the performance hit. | |
102 | ||
103 | =head1 MAKING PERL ERRORS APPEAR IN THE BROWSER WINDOW | |
104 | ||
105 | If you want to send fatal (die, confess) errors to the browser, ask to | |
106 | import the special "fatalsToBrowser" subroutine: | |
107 | ||
108 | use CGI::Carp qw(fatalsToBrowser); | |
109 | die "Bad error here"; | |
110 | ||
111 | Fatal errors will now be echoed to the browser as well as to the log. CGI::Carp | |
112 | arranges to send a minimal HTTP header to the browser so that even errors that | |
113 | occur in the early compile phase will be seen. | |
114 | Nonfatal errors will still be directed to the log file only (unless redirected | |
115 | with carpout). | |
116 | ||
117 | =head2 Changing the default message | |
118 | ||
119 | By default, the software error message is followed by a note to | |
120 | contact the Webmaster by e-mail with the time and date of the error. | |
121 | If this message is not to your liking, you can change it using the | |
122 | set_message() routine. This is not imported by default; you should | |
123 | import it on the use() line: | |
124 | ||
125 | use CGI::Carp qw(fatalsToBrowser set_message); | |
126 | set_message("It's not a bug, it's a feature!"); | |
127 | ||
128 | You may also pass in a code reference in order to create a custom | |
129 | error message. At run time, your code will be called with the text | |
130 | of the error message that caused the script to die. Example: | |
131 | ||
132 | use CGI::Carp qw(fatalsToBrowser set_message); | |
133 | BEGIN { | |
134 | sub handle_errors { | |
135 | my $msg = shift; | |
136 | print "<h1>Oh gosh</h1>"; | |
137 | print "<p>Got an error: $msg</p>"; | |
138 | } | |
139 | set_message(\&handle_errors); | |
140 | } | |
141 | ||
142 | In order to correctly intercept compile-time errors, you should call | |
143 | set_message() from within a BEGIN{} block. | |
144 | ||
145 | =head1 MAKING WARNINGS APPEAR AS HTML COMMENTS | |
146 | ||
147 | It is now also possible to make non-fatal errors appear as HTML | |
148 | comments embedded in the output of your program. To enable this | |
149 | feature, export the new "warningsToBrowser" subroutine. Since sending | |
150 | warnings to the browser before the HTTP headers have been sent would | |
151 | cause an error, any warnings are stored in an internal buffer until | |
152 | you call the warningsToBrowser() subroutine with a true argument: | |
153 | ||
154 | use CGI::Carp qw(fatalsToBrowser warningsToBrowser); | |
155 | use CGI qw(:standard); | |
156 | print header(); | |
157 | warningsToBrowser(1); | |
158 | ||
159 | You may also give a false argument to warningsToBrowser() to prevent | |
160 | warnings from being sent to the browser while you are printing some | |
161 | content where HTML comments are not allowed: | |
162 | ||
163 | warningsToBrowser(0); # disable warnings | |
164 | print "<script type=\"text/javascript\"><!--\n"; | |
165 | print_some_javascript_code(); | |
166 | print "//--></script>\n"; | |
167 | warningsToBrowser(1); # re-enable warnings | |
168 | ||
169 | Note: In this respect warningsToBrowser() differs fundamentally from | |
170 | fatalsToBrowser(), which you should never call yourself! | |
171 | ||
172 | =head1 OVERRIDING THE NAME OF THE PROGRAM | |
173 | ||
174 | CGI::Carp includes the name of the program that generated the error or | |
175 | warning in the messages written to the log and the browser window. | |
176 | Sometimes, Perl can get confused about what the actual name of the | |
177 | executed program was. In these cases, you can override the program | |
178 | name that CGI::Carp will use for all messages. | |
179 | ||
180 | The quick way to do that is to tell CGI::Carp the name of the program | |
181 | in its use statement. You can do that by adding | |
182 | "name=cgi_carp_log_name" to your "use" statement. For example: | |
183 | ||
184 | use CGI::Carp qw(name=cgi_carp_log_name); | |
185 | ||
186 | . If you want to change the program name partway through the program, | |
187 | you can use the C<set_progname()> function instead. It is not | |
188 | exported by default, you must import it explicitly by saying | |
189 | ||
190 | use CGI::Carp qw(set_progname); | |
191 | ||
192 | Once you've done that, you can change the logged name of the program | |
193 | at any time by calling | |
194 | ||
195 | set_progname(new_program_name); | |
196 | ||
197 | You can set the program back to the default by calling | |
198 | ||
199 | set_progname(undef); | |
200 | ||
201 | Note that this override doesn't happen until after the program has | |
202 | compiled, so any compile-time errors will still show up with the | |
203 | non-overridden program name | |
204 | ||
205 | =head1 CHANGE LOG | |
206 | ||
207 | 1.05 carpout() added and minor corrections by Marc Hedlund | |
208 | <hedlund@best.com> on 11/26/95. | |
209 | ||
210 | 1.06 fatalsToBrowser() no longer aborts for fatal errors within | |
211 | eval() statements. | |
212 | ||
213 | 1.08 set_message() added and carpout() expanded to allow for FileHandle | |
214 | objects. | |
215 | ||
216 | 1.09 set_message() now allows users to pass a code REFERENCE for | |
217 | really custom error messages. croak and carp are now | |
218 | exported by default. Thanks to Gunther Birznieks for the | |
219 | patches. | |
220 | ||
221 | 1.10 Patch from Chris Dean (ctdean@cogit.com) to allow | |
222 | module to run correctly under mod_perl. | |
223 | ||
224 | 1.11 Changed order of > and < escapes. | |
225 | ||
226 | 1.12 Changed die() on line 217 to CORE::die to avoid B<-w> warning. | |
227 | ||
228 | 1.13 Added cluck() to make the module orthogonal with Carp. | |
229 | More mod_perl related fixes. | |
230 | ||
231 | 1.20 Patch from Ilmari Karonen (perl@itz.pp.sci.fi): Added | |
232 | warningsToBrowser(). Replaced <CODE> tags with <PRE> in | |
233 | fatalsToBrowser() output. | |
234 | ||
235 | 1.23 ineval() now checks both $^S and inspects the message for the "eval" pattern | |
236 | (hack alert!) in order to accomodate various combinations of Perl and | |
237 | mod_perl. | |
238 | ||
239 | 1.24 Patch from Scott Gifford (sgifford@suspectclass.com): Add support | |
240 | for overriding program name. | |
241 | ||
242 | 1.26 Replaced CORE::GLOBAL::die with the evil $SIG{__DIE__} because the | |
243 | former isn't working in some people's hands. There is no such thing | |
244 | as reliable exception handling in Perl. | |
245 | ||
246 | 1.27 Replaced tell STDOUT with bytes=tell STDOUT. | |
247 | ||
248 | =head1 AUTHORS | |
249 | ||
250 | Copyright 1995-2002, Lincoln D. Stein. All rights reserved. | |
251 | ||
252 | This library is free software; you can redistribute it and/or modify | |
253 | it under the same terms as Perl itself. | |
254 | ||
255 | Address bug reports and comments to: lstein@cshl.org | |
256 | ||
257 | =head1 SEE ALSO | |
258 | ||
259 | Carp, CGI::Base, CGI::BasePlus, CGI::Request, CGI::MiniSvr, CGI::Form, | |
260 | CGI::Response | |
261 | if (defined($CGI::Carp::PROGNAME)) | |
262 | { | |
263 | $file = $CGI::Carp::PROGNAME; | |
264 | } | |
265 | ||
266 | =cut | |
267 | ||
268 | require 5.000; | |
269 | use Exporter; | |
270 | #use Carp; | |
271 | BEGIN { | |
272 | require Carp; | |
273 | *CORE::GLOBAL::die = \&CGI::Carp::die; | |
274 | } | |
275 | ||
276 | use File::Spec; | |
277 | ||
278 | @ISA = qw(Exporter); | |
279 | @EXPORT = qw(confess croak carp); | |
280 | @EXPORT_OK = qw(carpout fatalsToBrowser warningsToBrowser wrap set_message set_progname cluck ^name= die); | |
281 | ||
282 | $main::SIG{__WARN__}=\&CGI::Carp::warn; | |
283 | ||
284 | $CGI::Carp::VERSION = '1.29'; | |
285 | $CGI::Carp::CUSTOM_MSG = undef; | |
286 | ||
287 | ||
288 | # fancy import routine detects and handles 'errorWrap' specially. | |
289 | sub import { | |
290 | my $pkg = shift; | |
291 | my(%routines); | |
292 | my(@name); | |
293 | ||
294 | if (@name=grep(/^name=/,@_)) | |
295 | { | |
296 | my($n) = (split(/=/,$name[0]))[1]; | |
297 | set_progname($n); | |
298 | @_=grep(!/^name=/,@_); | |
299 | } | |
300 | ||
301 | grep($routines{$_}++,@_,@EXPORT); | |
302 | $WRAP++ if $routines{'fatalsToBrowser'} || $routines{'wrap'}; | |
303 | $WARN++ if $routines{'warningsToBrowser'}; | |
304 | my($oldlevel) = $Exporter::ExportLevel; | |
305 | $Exporter::ExportLevel = 1; | |
306 | Exporter::import($pkg,keys %routines); | |
307 | $Exporter::ExportLevel = $oldlevel; | |
308 | $main::SIG{__DIE__} =\&CGI::Carp::die if $routines{'fatalsToBrowser'}; | |
309 | # $pkg->export('CORE::GLOBAL','die'); | |
310 | } | |
311 | ||
312 | # These are the originals | |
313 | sub realwarn { CORE::warn(@_); } | |
314 | sub realdie { CORE::die(@_); } | |
315 | ||
316 | sub id { | |
317 | my $level = shift; | |
318 | my($pack,$file,$line,$sub) = caller($level); | |
319 | my($dev,$dirs,$id) = File::Spec->splitpath($file); | |
320 | return ($file,$line,$id); | |
321 | } | |
322 | ||
323 | sub stamp { | |
324 | my $time = scalar(localtime); | |
325 | my $frame = 0; | |
326 | my ($id,$pack,$file,$dev,$dirs); | |
327 | if (defined($CGI::Carp::PROGNAME)) { | |
328 | $id = $CGI::Carp::PROGNAME; | |
329 | } else { | |
330 | do { | |
331 | $id = $file; | |
332 | ($pack,$file) = caller($frame++); | |
333 | } until !$file; | |
334 | } | |
335 | ($dev,$dirs,$id) = File::Spec->splitpath($id); | |
336 | return "[$time] $id: "; | |
337 | } | |
338 | ||
339 | sub set_progname { | |
340 | $CGI::Carp::PROGNAME = shift; | |
341 | return $CGI::Carp::PROGNAME; | |
342 | } | |
343 | ||
344 | ||
345 | sub warn { | |
346 | my $message = shift; | |
347 | my($file,$line,$id) = id(1); | |
348 | $message .= " at $file line $line.\n" unless $message=~/\n$/; | |
349 | _warn($message) if $WARN; | |
350 | my $stamp = stamp; | |
351 | $message=~s/^/$stamp/gm; | |
352 | realwarn $message; | |
353 | } | |
354 | ||
355 | sub _warn { | |
356 | my $msg = shift; | |
357 | if ($EMIT_WARNINGS) { | |
358 | # We need to mangle the message a bit to make it a valid HTML | |
359 | # comment. This is done by substituting similar-looking ISO | |
360 | # 8859-1 characters for <, > and -. This is a hack. | |
361 | $msg =~ tr/<>-/\253\273\255/; | |
362 | chomp $msg; | |
363 | print STDOUT "<!-- warning: $msg -->\n"; | |
364 | } else { | |
365 | push @WARNINGS, $msg; | |
366 | } | |
367 | } | |
368 | ||
369 | ||
370 | # The mod_perl package Apache::Registry loads CGI programs by calling | |
371 | # eval. These evals don't count when looking at the stack backtrace. | |
372 | sub _longmess { | |
373 | my $message = Carp::longmess(); | |
374 | $message =~ s,eval[^\n]+(ModPerl|Apache)/(?:Registry|Dispatch)\w*\.pm.*,,s | |
375 | if exists $ENV{MOD_PERL}; | |
376 | return $message; | |
377 | } | |
378 | ||
379 | sub ineval { | |
380 | (exists $ENV{MOD_PERL} ? 0 : $^S) || _longmess() =~ /eval [\{\']/m | |
381 | } | |
382 | ||
383 | sub die { | |
384 | my ($arg,@rest) = @_; | |
385 | realdie ($arg,@rest) if ineval(); | |
386 | ||
387 | if (!ref($arg)) { | |
388 | $arg = join("", ($arg,@rest)); | |
389 | my($file,$line,$id) = id(1); | |
390 | $arg .= " at $file line $line." unless $arg=~/\n$/; | |
391 | &fatalsToBrowser($arg) if $WRAP; | |
392 | if (($arg =~ /\n$/) || !exists($ENV{MOD_PERL})) { | |
393 | my $stamp = stamp; | |
394 | $arg=~s/^/$stamp/gm; | |
395 | } | |
396 | if ($arg !~ /\n$/) { | |
397 | $arg .= "\n"; | |
398 | } | |
399 | } | |
400 | realdie $arg; | |
401 | } | |
402 | ||
403 | sub set_message { | |
404 | $CGI::Carp::CUSTOM_MSG = shift; | |
405 | return $CGI::Carp::CUSTOM_MSG; | |
406 | } | |
407 | ||
408 | sub confess { CGI::Carp::die Carp::longmess @_; } | |
409 | sub croak { CGI::Carp::die Carp::shortmess @_; } | |
410 | sub carp { CGI::Carp::warn Carp::shortmess @_; } | |
411 | sub cluck { CGI::Carp::warn Carp::longmess @_; } | |
412 | ||
413 | # We have to be ready to accept a filehandle as a reference | |
414 | # or a string. | |
415 | sub carpout { | |
416 | my($in) = @_; | |
417 | my($no) = fileno(to_filehandle($in)); | |
418 | realdie("Invalid filehandle $in\n") unless defined $no; | |
419 | ||
420 | open(SAVEERR, ">&STDERR"); | |
421 | open(STDERR, ">&$no") or | |
422 | ( print SAVEERR "Unable to redirect STDERR: $!\n" and exit(1) ); | |
423 | } | |
424 | ||
425 | sub warningsToBrowser { | |
426 | $EMIT_WARNINGS = @_ ? shift : 1; | |
427 | _warn(shift @WARNINGS) while $EMIT_WARNINGS and @WARNINGS; | |
428 | } | |
429 | ||
430 | # headers | |
431 | sub fatalsToBrowser { | |
432 | my($msg) = @_; | |
433 | $msg=~s/&/&/g; | |
434 | $msg=~s/>/>/g; | |
435 | $msg=~s/</</g; | |
436 | $msg=~s/\"/"/g; | |
437 | my($wm) = $ENV{SERVER_ADMIN} ? | |
438 | qq[the webmaster (<a href="mailto:$ENV{SERVER_ADMIN}">$ENV{SERVER_ADMIN}</a>)] : | |
439 | "this site's webmaster"; | |
440 | my ($outer_message) = <<END; | |
441 | For help, please send mail to $wm, giving this error message | |
442 | and the time and date of the error. | |
443 | END | |
444 | ; | |
445 | my $mod_perl = exists $ENV{MOD_PERL}; | |
446 | ||
447 | if ($CUSTOM_MSG) { | |
448 | if (ref($CUSTOM_MSG) eq 'CODE') { | |
449 | print STDOUT "Content-type: text/html\n\n" | |
450 | unless $mod_perl; | |
451 | &$CUSTOM_MSG($msg); # nicer to perl 5.003 users | |
452 | return; | |
453 | } else { | |
454 | $outer_message = $CUSTOM_MSG; | |
455 | } | |
456 | } | |
457 | ||
458 | my $mess = <<END; | |
459 | <h1>Software error:</h1> | |
460 | <pre>$msg</pre> | |
461 | <p> | |
462 | $outer_message | |
463 | </p> | |
464 | END | |
465 | ; | |
466 | ||
467 | if ($mod_perl) { | |
468 | my $r; | |
469 | if ($ENV{MOD_PERL_API_VERSION} && $ENV{MOD_PERL_API_VERSION} == 2) { | |
470 | $mod_perl = 2; | |
471 | require Apache2::RequestRec; | |
472 | require Apache2::RequestIO; | |
473 | require Apache2::RequestUtil; | |
474 | require APR::Pool; | |
475 | require ModPerl::Util; | |
476 | require Apache2::Response; | |
477 | $r = Apache2::RequestUtil->request; | |
478 | } | |
479 | else { | |
480 | $r = Apache->request; | |
481 | } | |
482 | # If bytes have already been sent, then | |
483 | # we print the message out directly. | |
484 | # Otherwise we make a custom error | |
485 | # handler to produce the doc for us. | |
486 | if ($r->bytes_sent) { | |
487 | $r->print($mess); | |
488 | $mod_perl == 2 ? ModPerl::Util::exit(0) : $r->exit; | |
489 | } else { | |
490 | # MSIE won't display a custom 500 response unless it is >512 bytes! | |
491 | if ($ENV{HTTP_USER_AGENT} =~ /MSIE/) { | |
492 | $mess = "<!-- " . (' ' x 513) . " -->\n$mess"; | |
493 | } | |
494 | $r->custom_response(500,$mess); | |
495 | } | |
496 | } else { | |
497 | my $bytes_written = eval{tell STDOUT}; | |
498 | if (defined $bytes_written && $bytes_written > 0) { | |
499 | print STDOUT $mess; | |
500 | } | |
501 | else { | |
502 | print STDOUT "Content-type: text/html\n\n"; | |
503 | print STDOUT $mess; | |
504 | } | |
505 | } | |
506 | ||
507 | warningsToBrowser(1); # emit warnings before dying | |
508 | } | |
509 | ||
510 | # Cut and paste from CGI.pm so that we don't have the overhead of | |
511 | # always loading the entire CGI module. | |
512 | sub to_filehandle { | |
513 | my $thingy = shift; | |
514 | return undef unless $thingy; | |
515 | return $thingy if UNIVERSAL::isa($thingy,'GLOB'); | |
516 | return $thingy if UNIVERSAL::isa($thingy,'FileHandle'); | |
517 | if (!ref($thingy)) { | |
518 | my $caller = 1; | |
519 | while (my $package = caller($caller++)) { | |
520 | my($tmp) = $thingy=~/[\':]/ ? $thingy : "$package\:\:$thingy"; | |
521 | return $tmp if defined(fileno($tmp)); | |
522 | } | |
523 | } | |
524 | return undef; | |
525 | } | |
526 | ||
527 | 1; |