permission problems between commandline and CGI

parkprimus has asked for the wisdom of the Perl Monks concerning the following question:

Monks, This is a problem that has been plaguing me for a week now and I am out of ideas. The code below works fine in command line (RH9) but as soon as I try the browser it gives me two errors. Any ideas will be appreciated. Thank you Monks!

#!/usr/bin/perl

use CGI qw(:standard);

my $cgi = new CGI;
$i = 0;
$connect = 0;

make_connection();
cut_connection();

sub make_html {

        use Spreadsheet::ParseExcel::Simple;

        print $cgi->header();
        print $cgi->start_html('7513 Interface Descriptions');
        print "<H1><center>7513 Interface Descriptions</H1>\n";
        print "<Table border = 1>\n";

        $xls = Spreadsheet::ParseExcel::Simple->read('/root/FLA_DHRS/S
+HRHZ006/7513.xls');
        foreach $sheet ($xls->sheets) {
                while ($sheet->has_data) {
                        @data = $sheet->next_row;
                        print "  <tr>\n";
                        #print "@data\n";
                        foreach $element (@data) {

                                if ($i <= 2) {
                         print "<td><b><center>$element</td></b></cent
+er>\n";
                                        $i++;
                                }
                                else {
                                        print "<td><center>$element</t
+d></ceneter>\n";
                                }
                        }
                print "  </tr>\n";
                }
        }
        print end_html;
}

sub make_connection {
 if($connect eq 0) {
                system("/usr/local/bin/ncpmount -S server
-A ip address -V /vol2/ISPSNC/PortAssignments 
-U username -P password /root/FLA_DHRS/SHRHZ006");
                $connect = 1;
         }
        else {
                $connect = 0;
                error();
        }
        if($connect eq 1) {
                make_html();
        }
}

sub cut_connection {

        if ($connect eq 1) {
                system('ncpumount -S server');
        }
}

sub error {
        print $cgi->header();
        print $cgi->start('Error');
        print "<center>";
        print "<H2> Error: Could not connect to server </H2>";
        print "Please Try again later";
        print "<HR></center>";
        print end_html;
}
[download]

Error 1

Cannot to mount on /root/FLA_DHRS/SHRHZ006: Operation not permitted

Error 2

Can't call method "sheets" on an undefined value at /var/www/cgi-bin/perldev/excel.cgi line 22.

Retitled from "Racking My Brain!" by Chady

Comment on permission problems between commandline and CGI Download Code

Replies are listed 'Best First'.
Re: permission problems between commandline and CGI by Abigail-II (Bishop) on Jan 27, 2004 at 22:54 UTC
Cannot to mount on /root/FLA_DHRS/SHRHZ006: Operation not permitted That's not a Perl error, but an error generated from an external command. Can't call method "sheets" on an undefined value at /var/www/cgi-bin/perldev/excel.cgi line 22. That means that in `$xls->sheets`, `$xls` is undefined. `$xls` is whatever is returned by `Spreadsheet::ParseExcel::Simple->read('/root/FLA_DHRS/SHRHZ006/7513.xls');` You don't check whether that returns an object or not. Abigail	[reply] [d/l] [select]
Re: permission problems between commandline and CGI by b10m (Vicar) on Jan 27, 2004 at 22:54 UTC
I'd say your web daemon user (probably "nobody", or "www") is not allowed to execute `ncpmount`. And the same user is probably also not allowed to jiggle around in /root/ (and there's nothing wrong with that ;). You've got to really ask yourself wheter you want to mount something through a webinterface, for it's not very secure. -- b10m	[reply]
Re: permission problems between commandline and CGI by borisz (Canon) on Jan 27, 2004 at 23:02 UTC
This means that the uid/gid pair of your webserver is not allowed to mount something. see `chmod/chown` or look into your httpd.conf under `User` and `Group` settings. The second error looks like a result from the first. You try to read a file that can not reached. Boris	[reply] [d/l] [select]
subtle details by Anonymous Monk on Jan 28, 2004 at 01:26 UTC
As most has been already to varying degrees been pointed out accurately, I will comment on some subtle but essential details (forgive my offtopicness): 1.) Numerical comparisons are handled by the == comparator Substitute `if ($connect eq 1) { }` [download] with `if ($connect) { }` [download] or (unnecessary) `if ($connect == 1) { }` [download] 2.) Use here docs Instead of saying `print "<center>"; print "<H2> Error: Could not connect to server </H2>"; print "Please Try again later"; print "<HR></center>";` [download] use `print <<'HTML'; <center> <H2> Error: Could not connect to server </H2> Please Try again later <HR></center> HTML` [download] 3.) use strict && use warnings Always use strict. Always use warnings. Those will prevent a good amount of self-induced headache; latter should be omitted in ``production" code.	[reply] [d/l] [select]
Re: permission problems between commandline and CGI by eoin (Monk) on Jan 27, 2004 at 23:12 UTC
"Error 1 Cannot to mount on /root/FLA_DHRS/SHRHZ006: Operation not permitted" I'm no expert on these matters but this clearly tells me that you do not have adequit permissions to access this directory. Try moving the file to a directory that you can access. "Error 2 Can't call method "sheets" on an undefined value at /var/www/cgi-bin/perldev/excel.cgi line 22." You get this error because `$xls` is undefined because `$xls = Spreadsheet::ParseExcel::Simple->read('/root/FLA_DHRS/SHRHZ006/7513.xls')` can't set `$xls` because it can't access the specified file. So I think that all you have to do is change the permissions for that directory/file or move the file to another directory, one that you can access. Hope it helps Eoin	[reply] [d/l] [select]


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