lib/CGI/Carp.pm

package CGI::Carp;

=head1 NAME

B<CGI::Carp> - CGI routines for writing to the HTTPD (or other) error log

=head1 SYNOPSIS

    use CGI::Carp;

    croak "We're outta here!";
    confess "It was my fault: $!";
    carp "It was your fault!";   
    warn "I'm confused";
    die  "I'm dying.\n";

    use CGI::Carp qw(cluck);
    cluck "I wouldn't do that if I were you";

    use CGI::Carp qw(fatalsToBrowser);
    die "Fatal error messages are now sent to browser";

=head1 DESCRIPTION

CGI scripts have a nasty habit of leaving warning messages in the error
logs that are neither time stamped nor fully identified.  Tracking down
the script that caused the error is a pain.  This fixes that.  Replace
the usual

    use Carp;

with

    use CGI::Carp

And the standard warn(), die (), croak(), confess() and carp() calls
will automagically be replaced with functions that write out nicely
time-stamped messages to the HTTP server error log.

For example:

   [Fri Nov 17 21:40:43 1995] test.pl: I'm confused at test.pl line 3.
   [Fri Nov 17 21:40:43 1995] test.pl: Got an error message: Permission denied.
   [Fri Nov 17 21:40:43 1995] test.pl: I'm dying.

=head1 REDIRECTING ERROR MESSAGES

By default, error messages are sent to STDERR.  Most HTTPD servers
direct STDERR to the server's error log.  Some applications may wish
to keep private error logs, distinct from the server's error log, or
they may wish to direct error messages to STDOUT so that the browser
will receive them.

The C<carpout()> function is provided for this purpose.  Since
carpout() is not exported by default, you must import it explicitly by
saying

   use CGI::Carp qw(carpout);

The carpout() function requires one argument, which should be a
reference to an open filehandle for writing errors.  It should be
called in a C<BEGIN> block at the top of the CGI application so that
compiler errors will be caught.  Example:

   BEGIN {
     use CGI::Carp qw(carpout);
     open(LOG, ">>/usr/local/cgi-logs/mycgi-log") or
       die("Unable to open mycgi-log: $!\n");
     carpout(LOG);
   }

carpout() does not handle file locking on the log for you at this point.

The real STDERR is not closed -- it is moved to CGI::Carp::SAVEERR.  Some
servers, when dealing with CGI scripts, close their connection to the
browser when the script closes STDOUT and STDERR.  CGI::Carp::SAVEERR is there to
prevent this from happening prematurely.

You can pass filehandles to carpout() in a variety of ways.  The "correct"
way according to Tom Christiansen is to pass a reference to a filehandle 
GLOB:

    carpout(\*LOG);

This looks weird to mere mortals however, so the following syntaxes are
accepted as well:

    carpout(LOG);
    carpout(main::LOG);
    carpout(main'LOG);
    carpout(\LOG);
    carpout(\'main::LOG');

    ... and so on

FileHandle and other objects work as well.

Use of carpout() is not great for performance, so it is recommended
for debugging purposes or for moderate-use applications.  A future
version of this module may delay redirecting STDERR until one of the
CGI::Carp methods is called to prevent the performance hit.

=head1 MAKING PERL ERRORS APPEAR IN THE BROWSER WINDOW

If you want to send fatal (die, confess) errors to the browser, ask to 
import the special "fatalsToBrowser" subroutine:

    use CGI::Carp qw(fatalsToBrowser);
    die "Bad error here";

Fatal errors will now be echoed to the browser as well as to the log.  CGI::Carp
arranges to send a minimal HTTP header to the browser so that even errors that
occur in the early compile phase will be seen.
Nonfatal errors will still be directed to the log file only (unless redirected
with carpout).

=head2 Changing the default message

By default, the software error message is followed by a note to
contact the Webmaster by e-mail with the time and date of the error.
If this message is not to your liking, you can change it using the
set_message() routine.  This is not imported by default; you should
import it on the use() line:

    use CGI::Carp qw(fatalsToBrowser set_message);
    set_message("It's not a bug, it's a feature!");

You may also pass in a code reference in order to create a custom
error message.  At run time, your code will be called with the text
of the error message that caused the script to die.  Example:

    use CGI::Carp qw(fatalsToBrowser set_message);
    BEGIN {
       sub handle_errors {
          my $msg = shift;
          print "<h1>Oh gosh</h1>";
          print "<p>Got an error: $msg</p>";
      }
      set_message(\&handle_errors);
    }

In order to correctly intercept compile-time errors, you should call
set_message() from within a BEGIN{} block.

=head1 MAKING WARNINGS APPEAR AS HTML COMMENTS

It is now also possible to make non-fatal errors appear as HTML
comments embedded in the output of your program.  To enable this
feature, export the new "warningsToBrowser" subroutine.  Since sending
warnings to the browser before the HTTP headers have been sent would
cause an error, any warnings are stored in an internal buffer until
you call the warningsToBrowser() subroutine with a true argument:

    use CGI::Carp qw(fatalsToBrowser warningsToBrowser);
    use CGI qw(:standard);
    print header();
    warningsToBrowser(1);

You may also give a false argument to warningsToBrowser() to prevent
warnings from being sent to the browser while you are printing some
content where HTML comments are not allowed:

    warningsToBrowser(0);    # disable warnings
    print "<script type=\"text/javascript\"><!--\n";
    print_some_javascript_code();
    print "//--></script>\n";
    warningsToBrowser(1);    # re-enable warnings

Note: In this respect warningsToBrowser() differs fundamentally from
fatalsToBrowser(), which you should never call yourself!

=head1 OVERRIDING THE NAME OF THE PROGRAM

CGI::Carp includes the name of the program that generated the error or
warning in the messages written to the log and the browser window.
Sometimes, Perl can get confused about what the actual name of the
executed program was.  In these cases, you can override the program
name that CGI::Carp will use for all messages.

The quick way to do that is to tell CGI::Carp the name of the program
in its use statement.  You can do that by adding
"name=cgi_carp_log_name" to your "use" statement.  For example:

    use CGI::Carp qw(name=cgi_carp_log_name);

.  If you want to change the program name partway through the program,
you can use the C<set_progname()> function instead.  It is not
exported by default, you must import it explicitly by saying

    use CGI::Carp qw(set_progname);

Once you've done that, you can change the logged name of the program
at any time by calling

    set_progname(new_program_name);

You can set the program back to the default by calling

    set_progname(undef);

Note that this override doesn't happen until after the program has
compiled, so any compile-time errors will still show up with the
non-overridden program name
  
=head1 CHANGE LOG

1.05 carpout() added and minor corrections by Marc Hedlund
     <hedlund@best.com> on 11/26/95.

1.06 fatalsToBrowser() no longer aborts for fatal errors within
     eval() statements.

1.08 set_message() added and carpout() expanded to allow for FileHandle
     objects.

1.09 set_message() now allows users to pass a code REFERENCE for 
     really custom error messages.  croak and carp are now
     exported by default.  Thanks to Gunther Birznieks for the
     patches.

1.10 Patch from Chris Dean (ctdean@cogit.com) to allow 
     module to run correctly under mod_perl.

1.11 Changed order of &gt; and &lt; escapes.

1.12 Changed die() on line 217 to CORE::die to avoid B<-w> warning.

1.13 Added cluck() to make the module orthogonal with Carp.
     More mod_perl related fixes.

1.20 Patch from Ilmari Karonen (perl@itz.pp.sci.fi):  Added
     warningsToBrowser().  Replaced <CODE> tags with <PRE> in
     fatalsToBrowser() output.

1.23 ineval() now checks both $^S and inspects the message for the "eval" pattern
     (hack alert!) in order to accomodate various combinations of Perl and
     mod_perl.

1.24 Patch from Scott Gifford (sgifford@suspectclass.com): Add support
     for overriding program name.

1.26 Replaced CORE::GLOBAL::die with the evil $SIG{__DIE__} because the
     former isn't working in some people's hands.  There is no such thing
     as reliable exception handling in Perl.

1.27 Replaced tell STDOUT with bytes=tell STDOUT.

=head1 AUTHORS

Copyright 1995-2002, Lincoln D. Stein.  All rights reserved.  

This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.

Address bug reports and comments to: lstein@cshl.org

=head1 SEE ALSO

Carp, CGI::Base, CGI::BasePlus, CGI::Request, CGI::MiniSvr, CGI::Form,
CGI::Response
    if (defined($CGI::Carp::PROGNAME)) 
    {
      $file = $CGI::Carp::PROGNAME;
    }

=cut

require 5.000;
use Exporter;
#use Carp;
BEGIN { 
  require Carp; 
  *CORE::GLOBAL::die = \&CGI::Carp::die;
}

use File::Spec;

@ISA = qw(Exporter);
@EXPORT = qw(confess croak carp);
@EXPORT_OK = qw(carpout fatalsToBrowser warningsToBrowser wrap set_message set_progname cluck ^name= die);

$main::SIG{__WARN__}=\&CGI::Carp::warn;

$CGI::Carp::VERSION    = '1.27';
$CGI::Carp::CUSTOM_MSG = undef;


# fancy import routine detects and handles 'errorWrap' specially.
sub import {
    my $pkg = shift;
    my(%routines);
    my(@name);
  
    if (@name=grep(/^name=/,@_))
      {
        my($n) = (split(/=/,$name[0]))[1];
        set_progname($n);
        @_=grep(!/^name=/,@_);
      }

    grep($routines{$_}++,@_,@EXPORT);
    $WRAP++ if $routines{'fatalsToBrowser'} || $routines{'wrap'};
    $WARN++ if $routines{'warningsToBrowser'};
    my($oldlevel) = $Exporter::ExportLevel;
    $Exporter::ExportLevel = 1;
    Exporter::import($pkg,keys %routines);
    $Exporter::ExportLevel = $oldlevel;
    $main::SIG{__DIE__} =\&CGI::Carp::die if $routines{'fatalsToBrowser'};
#    $pkg->export('CORE::GLOBAL','die');
}

# These are the originals
sub realwarn { CORE::warn(@_); }
sub realdie { CORE::die(@_); }

sub id {
    my $level = shift;
    my($pack,$file,$line,$sub) = caller($level);
    my($dev,$dirs,$id) = File::Spec->splitpath($file);
    return ($file,$line,$id);
}

sub stamp {
    my $time = scalar(localtime);
    my $frame = 0;
    my ($id,$pack,$file,$dev,$dirs);
    if (defined($CGI::Carp::PROGNAME)) {
        $id = $CGI::Carp::PROGNAME;
    } else {
        do {
          $id = $file;
          ($pack,$file) = caller($frame++);
        } until !$file;
    }
    ($dev,$dirs,$id) = File::Spec->splitpath($id);
    return "[$time] $id: ";
}

sub set_progname {
    $CGI::Carp::PROGNAME = shift;
    return $CGI::Carp::PROGNAME;
}


sub warn {
    my $message = shift;
    my($file,$line,$id) = id(1);
    $message .= " at $file line $line.\n" unless $message=~/\n$/;
    _warn($message) if $WARN;
    my $stamp = stamp;
    $message=~s/^/$stamp/gm;
    realwarn $message;
}

sub _warn {
    my $msg = shift;
    if ($EMIT_WARNINGS) {
        # We need to mangle the message a bit to make it a valid HTML
        # comment.  This is done by substituting similar-looking ISO
        # 8859-1 characters for <, > and -.  This is a hack.
        $msg =~ tr/<>-/\253\273\255/;
        chomp $msg;
        print STDOUT "<!-- warning: $msg -->\n";
    } else {
        push @WARNINGS, $msg;
    }
}


# The mod_perl package Apache::Registry loads CGI programs by calling
# eval.  These evals don't count when looking at the stack backtrace.
sub _longmess {
    my $message = Carp::longmess();
    $message =~ s,eval[^\n]+(ModPerl|Apache)/Registry\w*\.pm.*,,s
        if exists $ENV{MOD_PERL};
    return $message;
}

sub ineval {
  (exists $ENV{MOD_PERL} ? 0 : $^S) || _longmess() =~ /eval [\{\']/m
}

sub die {
  my ($arg) = @_;
  realdie @_ if ineval;
  if (!ref($arg)) {
    $arg = join("", @_);
    my($file,$line,$id) = id(1);
    $arg .= " at $file line $line." unless $arg=~/\n$/;
    &fatalsToBrowser($arg) if $WRAP;
    if (($arg =~ /\n$/) || !exists($ENV{MOD_PERL})) {
      my $stamp = stamp;
      $arg=~s/^/$stamp/gm;
    }
    if ($arg !~ /\n$/) {
      $arg .= "\n";
    }
  }
  realdie $arg;
}

sub set_message {
    $CGI::Carp::CUSTOM_MSG = shift;
    return $CGI::Carp::CUSTOM_MSG;
}

sub confess { CGI::Carp::die Carp::longmess @_; }
sub croak   { CGI::Carp::die Carp::shortmess @_; }
sub carp    { CGI::Carp::warn Carp::shortmess @_; }
sub cluck   { CGI::Carp::warn Carp::longmess @_; }

# We have to be ready to accept a filehandle as a reference
# or a string.
sub carpout {
    my($in) = @_;
    my($no) = fileno(to_filehandle($in));
    realdie("Invalid filehandle $in\n") unless defined $no;
    
    open(SAVEERR, ">&STDERR");
    open(STDERR, ">&$no") or 
        ( print SAVEERR "Unable to redirect STDERR: $!\n" and exit(1) );
}

sub warningsToBrowser {
    $EMIT_WARNINGS = @_ ? shift : 1;
    _warn(shift @WARNINGS) while $EMIT_WARNINGS and @WARNINGS;
}

# headers
sub fatalsToBrowser {
  my($msg) = @_;
  $msg=~s/&/&amp;/g;
  $msg=~s/>/&gt;/g;
  $msg=~s/</&lt;/g;
  $msg=~s/\"/&quot;/g;
  my($wm) = $ENV{SERVER_ADMIN} ? 
    qq[the webmaster (<a href="mailto:$ENV{SERVER_ADMIN}">$ENV{SERVER_ADMIN}</a>)] :
      "this site's webmaster";
  my ($outer_message) = <<END;
For help, please send mail to $wm, giving this error message 
and the time and date of the error.
END
  ;
  my $mod_perl = exists $ENV{MOD_PERL};

  warningsToBrowser(1);    # emit warnings before dying

  if ($CUSTOM_MSG) {
    if (ref($CUSTOM_MSG) eq 'CODE') {
      print STDOUT "Content-type: text/html\n\n" 
        unless $mod_perl;
      &$CUSTOM_MSG($msg); # nicer to perl 5.003 users
      return;
    } else {
      $outer_message = $CUSTOM_MSG;
    }
  }

  my $mess = <<END;
<h1>Software error:</h1>
<pre>$msg</pre>
<p>
$outer_message
</p>
END
  ;

  if ($mod_perl) {
    require mod_perl;
    if ($mod_perl::VERSION >= 1.99) {
      $mod_perl = 2;
      require Apache::RequestRec;
      require Apache::RequestIO;
      require Apache::RequestUtil;
      require APR::Pool;
      require ModPerl::Util;
      require Apache::Response;
    }
    my $r = Apache->request;
    # If bytes have already been sent, then
    # we print the message out directly.
    # Otherwise we make a custom error
    # handler to produce the doc for us.
    if ($r->bytes_sent) {
      $r->print($mess);
      $mod_perl == 2 ? ModPerl::Util::exit(0) : $r->exit;
    } else {
      # MSIE won't display a custom 500 response unless it is >512 bytes!
      if ($ENV{HTTP_USER_AGENT} =~ /MSIE/) {
        $mess = "<!-- " . (' ' x 513) . " -->\n$mess";
      }
      $r->custom_response(500,$mess);
    }
  } else {
    my $bytes_written = eval{tell STDOUT};
    if (defined $bytes_written && $bytes_written > 0) {
        print STDOUT $mess;
    }
    else {
        print STDOUT "Content-type: text/html\n\n";
        print STDOUT $mess;
    }
  }
}

# Cut and paste from CGI.pm so that we don't have the overhead of
# always loading the entire CGI module.
sub to_filehandle {
    my $thingy = shift;
    return undef unless $thingy;
    return $thingy if UNIVERSAL::isa($thingy,'GLOB');
    return $thingy if UNIVERSAL::isa($thingy,'FileHandle');
    if (!ref($thingy)) {
        my $caller = 1;
        while (my $package = caller($caller++)) {
            my($tmp) = $thingy=~/[\':]/ ? $thingy : "$package\:\:$thingy"; 
            return $tmp if defined(fileno($tmp));
        }
    }
    return undef;
}

1;
1	wakaba	1.1	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 $SIG{__DIE__} because the
243			former isn't working in some people's hands. There is no such thing
244			as reliable exception handling in Perl.
245
246	wakaba	1.2	1.27 Replaced tell STDOUT with bytes=tell STDOUT.
247
248	wakaba	1.1	=head1 AUTHORS
249
250			Copyright 1995-2002, Lincoln D. Stein. All rights reserved.
251
252			This library is free software; you can redistribute it and/or modify
253			it under the same terms as Perl itself.
254
255			Address bug reports and comments to: lstein@cshl.org
256
257			=head1 SEE ALSO
258
259			Carp, CGI::Base, CGI::BasePlus, CGI::Request, CGI::MiniSvr, CGI::Form,
260			CGI::Response
261			if (defined($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	wakaba	1.2	$CGI::Carp::VERSION = '1.27';
285	wakaba	1.1	$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\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) = @_;
385			realdie @_ if ineval;
386			if (!ref($arg)) {
387			$arg = join("", @_);
388			my($file,$line,$id) = id(1);
389			$arg .= " at $file line $line." unless $arg=~/\n$/;
390			&fatalsToBrowser($arg) if $WRAP;
391			if (($arg =~ /\n$/) \|\| !exists($ENV{MOD_PERL})) {
392			my $stamp = stamp;
393			$arg=~s/^/$stamp/gm;
394			}
395			if ($arg !~ /\n$/) {
396			$arg .= "\n";
397			}
398			}
399			realdie $arg;
400			}
401
402			sub set_message {
403			$CGI::Carp::CUSTOM_MSG = shift;
404			return $CGI::Carp::CUSTOM_MSG;
405			}
406
407			sub confess { CGI::Carp::die Carp::longmess @_; }
408			sub croak { CGI::Carp::die Carp::shortmess @_; }
409			sub carp { CGI::Carp::warn Carp::shortmess @_; }
410			sub cluck { CGI::Carp::warn Carp::longmess @_; }
411
412			# We have to be ready to accept a filehandle as a reference
413			# or a string.
414			sub carpout {
415			my($in) = @_;
416			my($no) = fileno(to_filehandle($in));
417			realdie("Invalid filehandle $in\n") unless defined $no;
418
419			open(SAVEERR, ">&STDERR");
420			open(STDERR, ">&$no") or
421			( print SAVEERR "Unable to redirect STDERR: $!\n" and exit(1) );
422			}
423
424			sub warningsToBrowser {
425			$EMIT_WARNINGS = @_ ? shift : 1;
426			_warn(shift @WARNINGS) while $EMIT_WARNINGS and @WARNINGS;
427			}
428
429			# headers
430			sub fatalsToBrowser {
431			my($msg) = @_;
432			$msg=~s/&/&/g;
433			$msg=~s/>/>/g;
434			$msg=~s/</</g;
435			$msg=~s/\"/"/g;
436			my($wm) = $ENV{SERVER_ADMIN} ?
437			qq[the webmaster (<a href="mailto:$ENV{SERVER_ADMIN}">$ENV{SERVER_ADMIN}</a>)] :
438			"this site's webmaster";
439			my ($outer_message) = <<END;
440			For help, please send mail to $wm, giving this error message
441			and the time and date of the error.
442			END
443			;
444			my $mod_perl = exists $ENV{MOD_PERL};
445
446			warningsToBrowser(1); # emit warnings before dying
447
448			if ($CUSTOM_MSG) {
449			if (ref($CUSTOM_MSG) eq 'CODE') {
450			print STDOUT "Content-type: text/html\n\n"
451			unless $mod_perl;
452			&$CUSTOM_MSG($msg); # nicer to perl 5.003 users
453			return;
454			} else {
455			$outer_message = $CUSTOM_MSG;
456			}
457			}
458
459			my $mess = <<END;
460			<h1>Software error:</h1>
461			<pre>$msg</pre>
462			<p>
463			$outer_message
464			</p>
465			END
466			;
467
468			if ($mod_perl) {
469			require mod_perl;
470			if ($mod_perl::VERSION >= 1.99) {
471			$mod_perl = 2;
472			require Apache::RequestRec;
473			require Apache::RequestIO;
474			require Apache::RequestUtil;
475			require APR::Pool;
476			require ModPerl::Util;
477			require Apache::Response;
478			}
479			my $r = Apache->request;
480			# If bytes have already been sent, then
481			# we print the message out directly.
482			# Otherwise we make a custom error
483			# handler to produce the doc for us.
484			if ($r->bytes_sent) {
485			$r->print($mess);
486			$mod_perl == 2 ? ModPerl::Util::exit(0) : $r->exit;
487			} else {
488			# MSIE won't display a custom 500 response unless it is >512 bytes!
489			if ($ENV{HTTP_USER_AGENT} =~ /MSIE/) {
490			$mess = "<!-- " . (' ' x 513) . " -->\n$mess";
491			}
492			$r->custom_response(500,$mess);
493			}
494			} else {
495	wakaba	1.2	my $bytes_written = eval{tell STDOUT};
496			if (defined $bytes_written && $bytes_written > 0) {
497	wakaba	1.1	print STDOUT $mess;
498			}
499			else {
500			print STDOUT "Content-type: text/html\n\n";
501			print STDOUT $mess;
502			}
503			}
504			}
505
506			# Cut and paste from CGI.pm so that we don't have the overhead of
507			# always loading the entire CGI module.
508			sub to_filehandle {
509			my $thingy = shift;
510			return undef unless $thingy;
511			return $thingy if UNIVERSAL::isa($thingy,'GLOB');
512			return $thingy if UNIVERSAL::isa($thingy,'FileHandle');
513			if (!ref($thingy)) {
514			my $caller = 1;
515			while (my $package = caller($caller++)) {
516			my($tmp) = $thingy=~/[\':]/ ? $thingy : "$package\:\:$thingy";
517			return $tmp if defined(fileno($tmp));
518			}
519			}
520			return undef;
521			}
522
523			1;