ActivePerl doesn’t output fatals to browser - perl

I'm using the following code to test the outputting of fatal errors to the browser:
use CGI;
use CGI::Carp qw(fatalsToBrowser);
die "test";
I am expecting to see some error in the browser, but there isn't any, I just get a regular 500 response. I forgot that I had custom error pages on for remote requests, and I now get Script failed to send data..
Also:
> perl -w index.pl
Status: 500
Content-type: text/html
<h1>Software error:</h1>
<pre>test at index.pl line 4.</pre>
<p>
For help, please send mail to this site's webmaster, giving this error message and the time and date of the error.
</p>
[Mon Feb 8 18:29:52 2010] index.pl: test at index.pl line 4.

Try printing a couple of new lines before anything. That signals the end of HTTP headers to the server as the 'CGI standard' says. Or you may be able to use something like this: (as copied from the Carp man page):
use CGI::Carp qw(set_die_handler);
BEGIN {
sub handle_errors {
my $msg = shift;
print "content-type: text/html\n\n";
print "<h1>Oh gosh</h1>";
print "<p>Got an error: $msg</p>";
}
set_die_handler(\&handle_errors);
}
If that doesn't work here are a few more tricks:
#!perl
BEGIN { $| = 1; print "\n\n" }
open STDERR, ">&STDOUT";
..And a few more tricks in this Perl Journal article.

Related

Perl script getting 500 Internal Server error, end of script output before headers

I have this script to send email. Everything works except that after the email is sent I receive the error below. It has to be something simple I am missing. I checked and cgi file is 755 and since it gets to the sub and executes its got to be coder error. Any help greatly appreciated.
Internal Server Error The server encountered an internal error or misconfiguration and was unable to complete your request. More information about this error may be available in the server error log. Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.
The error in the server log is:
[Tue Jan 17 16:00:23.475272 2023] [cgi:error] [pid 230679] [client 69.90.223.10:35014] End of script output before headers: test3.cgi
Here is the code I am using, Perl CGI on Linux
#!/usr/bin/perl -Tw
# use warnings;
use strict;
use Net::SMTP;
send_mail('mail.xxxxxxx.com', # Host
'order#xxxxxxxxx.com', #From
'yyyyyyy#gmail.com', #to
'Just a test, from mail.xxxxxx.com please ignore', #Message body
"Testing mail server email.\n" # Subject
);
exit;
sub send_mail {
my ($SMTP_HOST, $from, $to_addr, $body, $subject, $msg) = #_;
$msg = "MIME-Version: 1.0\n"
. "From: $from\n"
. "To: " . ( ref($to_addr) ? join(';', #$to_addr) : $to_addr ) . "\n"
. "Subject: $subject\n\n" # Double \n
. $body;
#
# Open a SMTP session
#
my $smtp = Net::SMTP->new( $SMTP_HOST,
Debug => 0, # Change to a 1 to turn on debug messages
Port => 587,
);
die("SMTP ERROR: Unable to open smtp session.\n")
if(!defined($smtp) || !($smtp));
die("Failed to set FROM address\n")
if (! ($smtp->mail( $from ) ) );
die("Failed to set receipient\n")
if (! ($smtp->recipient( ( ref($to_addr) ? #$to_addr : $to_addr ) ) ) );
$smtp->data( $msg );
$smtp->quit;
}
Checked File attributes they are 755
Since it ran the code an performed the send email the Char set should be correct
Being new to Perl not sure what else to check
This isn't a CGI program. You send no response for the request. Since there is no response (not even an invalid one), the script exits with nothing sent to standard output. The server realizes this is a problem, creates the 500 server error response, and adds to the error log that the script output ended before headers, which is the first thing the server expected to see.
You might want to start with a basic CGI tutorial to see how CGI works.
But, also realize that sending mail through a CGI program is a very 1990s thing to do. We don't typically do that anymore because we all figured out that letting anyone trigger mail through a public server was a bad idea.

Get reason for failed LWP::Simple head request

I have migrated my scrilpts from CentOS 7 to 8 and there's a new Perl version. I have the folowing snippet that uses head to check if a URL exists:
#!/bin/perl
use strict;
use warnings;
use LWP::Simple;
my $sitemapurl = "https://www.prosinger.net";
if (head($sitemapurl)) {
...
}
else {
print "The $sitemapurl doesn't exist\n";
exit(1);
}
It now always returns that the URL doesn't exist. I'm quite sure that this has to do something with https (I have perl-LWP-Protocol-https installed), but I'm not sure how to get any feedback information from head method to check what the error code is.
Any ideas?
You can use LWP::UserAgent instead of LWP::Simple, which allows you to get an error message:
my $ua = LWP::UserAgent->new;
my $sitemapurl = "https://www.prosinger.net";
my $req = $ua->head($sitemapurl);
if ($req->is_success) {
...
} else {
die "Could not head($sitemapurl): " . $req->status_line;
}
Running this code prints:
Could not head(https://www.prosinger.net): 403 Forbidden at head.pl line 15.
You can fix this (for this specific website; this will not work for all website) by setting a User-Agent in your LWP::UserAgent object:
my $ua = LWP::UserAgent->new( agent => 'anything seems to work' );
Of interest is the decoded_content method of HTTP::Response that allows you to get the content of the request (you don't need it in that case, but you might later):
my $req = $ua->get(...);
if ($req->is_success) {
my $content = $req->decoded_content;
...
}
Your code that uses LWP::Simple and Dada's version that switches to LWP::UserAgent are basically doing the same thing, except that you can get details of the error when using LWP::UserAgent.
Running the LWP::UserAgent version gives this error:
Could not head(https://www.prosinger.net): 500 Can't connect to www.prosinger.net:443 (SSL connect attempt failed error:2707307E:OCSP routines:OCSP_check_validity:status not yet valid)
And Googling that error message gives this SO answer as the first result. Is it possible that the clocks on your your client machine and the server are out of sync?

Why does my Perl CGI program fail with "Software error: ..."?

When I try to run my Perl CGI program, the returned web page tells me:
Software error: For help, please send mail to the webmaster (root#localhost), giving this error message and the time and date of the error.
Here is my code in one of the file:
#!/usr/bin/perl
use lib "/home/ecoopr/ecoopr.com/CPAN";
use CGI;
use CGI::FormBuilder;
use CGI::Session;
use CGI::Carp (fatalsToBrowser);
use CGI::Session;
use HTML::Template;
use MIME::Base64 ();
use strict;
require "./db_lib.pl";
require "./config.pl";
my $query = CGI->new;
my $url = $query->url();
my $hostname = $query->url(-base => 1);
my $login_url = $hostname . '/login.pl';
my $redir_url = $login_url . '?d=' . $url;
my $domain_name = get_domain_name();
my $helpful_msg = $query->param('m');
my $new_trusted_user_fname = $query->param('u');
my $action = $query->param('a');
$new_trusted_user_fname = MIME::Base64::decode($new_trusted_user_fname);
####### Colin: Added July 12, 2009 #######
my $view = $query->param('view');
my $offset = $query->param('offset');
####### Colin: Added July , 2009 #######
#print $session->header;
#print $new_trusted_user;
my $helpful_msg_txt = qq[];
my $helpful_msg_div = qq[];
if ($helpful_msg)
The "please send mail to the webmaster" message you see is a generic message that the web server gives you when anything goes wrong and nothing handles it. It's not at all interesting in terms of solving the actual problem. Check the error log to find possible relevant error output from your program.
And, go through my How do I troubleshoot my Perl CGI script? advice on finding the problem.
My guess is that you have a syntax error with that dangling if(). What you have posted isn't a valid Perl program.
Good luck,
is that something related to suexec module
Improper configuration of suExec can cause permission errors
The suEXEC feature provides Apache users the ability to run CGI and SSI programs under user IDs different from the user ID of the calling web server. Normally, when a CGI or SSI program executes, it runs as the same user who is running the web server.
apache recommends that you not consider using suEXEC.
http://httpd.apache.org/docs/2.2/suexec.html
From the StackOverflow page: How to trap program crashes with HTTP error code 500
I see that your include: use CGI::Carp (fatalsToBrowser);
... stifles the HTTP 500 error. Simply removing this will allow the programs to crash "properly".

Why does my simple fastCGI Perl script fail?

I'm not of the Perl world, so some of this is new to me. I'm running Ubuntu Hardy LTS with apache2 and mod_fcgid packages installed. I'd like to get MT4 running under fcgid rather than mod-cgi (it seems to run OK with plain-old CGI).
I can't seem to get even a simple Perl script to run under fcgid. I created a simple "Hello World" app and included the code from this previous question to test if FCGI is running.
I named my script HelloWorld.fcgi (currently fcgid is set to handle .fcgi files only). Code:
#!/usr/bin/perl
use FCGI;
print "Content-type: text/html\n\n";
print "Hello world.\n\n";
my $request = FCGI::Request();
if ( $request->IsFastCGI ) {
print "we're running under FastCGI!\n";
} else {
print "plain old boring CGI\n";
}
When run from the command line, it prints "plain old boring..." When invoked via an http request to apache, I get a 500 Internal Server error and the output of the script is printed to the Apache error log:
Content-type: text/html
Hello world.
we're running under FastCGI!
[Wed Dec 03 22:26:19 2008] [warn] (104)Connection reset by peer: mod_fcgid: read data from fastcgi server error.
[Wed Dec 03 22:26:19 2008] [error] [client 70.23.221.171] Premature end of script headers: HelloWorld.fcgi
[Wed Dec 03 22:26:25 2008] [notice] mod_fcgid: process /www/mt/HelloWorld.fcgi(14189) exit(communication error), terminated by calling exit(), return code: 0
When I run the .cgi version of the same code, it works fine. Any idea why the output of the script is going to the error log? Apache config is the default mod_fcgid config plus, in a VirtualHost directive:
ServerName test1.example.com
DocumentRoot /www/example
<Directory /www/example>
AllowOverride None
AddHandler cgi-script .cgi
AddHandler fcgid-script .fcgi
Options +ExecCGI +Includes +FollowSymLinks
</Directory>
The problem is that the "Content-Type" header is sent outside of the request loop. You must print the "Content-Type" header for every request. If you move
print "Content-type: text/html\n\n";
to the top of the request loop it should fix the problem.
Also, you need to loop over the requests or you'll get no benefit, so following the first poster's example:
my $request = FCGI::Request();
while($request->Accept() >= 0) {
print("Content-type: text/html\n\n");
}
I use CGI::Fast more than FCGI, but the idea is the same, I think. The goal of fast cgi is to load the program once, and iterate in a loop for every request.
FCGI's man page says :
use FCGI;
my $count = 0;
my $request = FCGI::Request();
while($request->Accept() >= 0) {
print("Content-type: text/html\r\n\r\n", ++$count);
}
Which means, you have to Accept the request before being able to print anything back to the browser.
Movable Type uses CGI::Fast for FastCGI. The typical FastCGI script runs in a loop, as mat described. A loop that uses CGI::Fast would look like this:
#!/usr/bin/perl
use strict;
use CGI::Fast;
my $count = 0;
while (my $q = CGI::Fast->new) {
print("Content-Type: text/plain\n\n");
print("Process ID: $$; Count is: " . ++$count);
}
I tested this script on a server with the FCGI and CGI::Fast modules installed and count increments as you'd expect. If the process id changes, count will go back to 1 and then increment within that process. Each process has it's own variable space of course.
For MT, enabling FastCGI a matter of renaming (or symlinking) the cgi scripts to 'fcgi' (or making the handler for 'cgi' scripts fcgid, but that won't work for mt-xmlrpc.cgi which isn't FastCGI friendly yet). You'll also need to add some directives to your mt-config.cgi file so that it knows the new script names. Like this:
AdminScript mt.fcgi
CommentsScript mt-comments.fcgi
And so forth. More documentation specific to FastCGI and Movable Type is available on movabletype.org.
Anyway, based on your server's error logs, it looks like FCGI is working, and being invoked properly, but your script just isn't running in a loop, waiting for the next request to come along. So your test script did accomplish the task -- reporting whether FastCGI is configured or not. So now you should be able to reconfigure MT to use FastCGI.

Why can't I connect to my CAS server with Perl's AuthCAS?

I'm attempting to use an existing CAS server to authenticate login for a Perl CGI web script and am using the AuthCAS Perl module (v 1.3.1). I can connect to the CAS server to get the service ticket but when I try to connect to validate the ticket my script returns with the following error from the IO::Socket::SSL module:
500 Can't connect to [CAS Server]:443 (Bad hostname '[CAS Server]')
([CAS Server] substituted for real server name)
Symptoms/Tests:
If I type the generated URL for the authentication into the web browser's location bar it returns just fine with the expected XML snippet. So it is not a bad host name.
If I generate a script without using the AuthCAS module but using the IO::Socket::SSL module directly to query the CAS server for validation on the generated service ticket the Perl script will run fine from the command line but not in the browser.
If I add the AuthCAS module into the script in item 2, the script no longer works on the command line and still doesn't work in the browser.
Here is the bare-bones script that produces the error:
#!/usr/bin/perl
use strict;
use warnings;
use CGI;
use AuthCAS;
use CGI::Carp qw( fatalsToBrowser );
my $id = $ENV{QUERY_STRING};
my $q = new CGI;
my $target = "http://localhost/cgi-bin/testCAS.cgi";
my $cas = new AuthCAS(casUrl => 'https://cas_server/cas');
if ($id eq ""){
my $login_url = $cas->getServerLoginURL($target);
printf "Location: $login_url\n\n";
exit 0;
} else {
print $q->header();
print "CAS TEST<br>\n";
## When coming back from the CAS server a ticket is provided in the QUERY_STRING
print "QUERY_STRING = " . $id . "</br>\n";
## $ST should contain the received Service Ticket
my $ST = $q->param('ticket');
my $user = $cas->validateST($target, $ST); #### This is what fails
printf "Error: %s\n", &AuthCAS::get_errors() unless (defined $user);
}
Any ideas on where the conflict might be?
The error is coming from the line directly above the snippet Cebjyre quoted namely
$ssl_socket = new IO::Socket::SSL(%ssl_options);
namely the socket creation. All of the input parameters are correct. I had edited the module to put in debug statements and print out all the parameters just before that call and they are all fine. Looks like I'm going to have to dive deeper into the IO::Socket::SSL module.
As usually happens when I post questions like this, I found the problem. It turns out the Crypt::SSLeay module was not installed or at least not up to date. Of course the error messages didn't give me any clues. Updating it and all the problems go away and things are working fine now.
Well, from the module source it looks like that IO::Socket error is coming from get_https2
[...]
unless ($ssl_socket) {
$errors = sprintf "error %s unable to connect https://%s:%s/\n",&IO::Socket::SSL::errstr,$host,$port;
return undef;
}
[...]
which is called by callCAS, which is called by validateST.
One option is to temporarily edit the module file to put some debug statements in if you can, but if I had to guess, I'd say the casUrl you are supplying isn't matching up to the _parse_url regex properly - maybe you have three slashes after the https?