#
# LON-CAPA helpers for cgi-bin scripts
#
# $Id: loncgi.pm,v 1.9 2008/11/28 20:39:43 raeburn Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# LON-CAPA is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#
#############################################
#############################################

=pod

=head1 NAME

loncgi

=head1 SYNOPSIS

Provides subroutines for checking a LON-CAPA cookie, loading the user's
environment, retrieving arguments passed in via a CGI's Query String,
checking access controls, providing a user with an explanation
when access is denied, and descriptions of various server status pages 
generated by CGI scripts which use these subroutines for authorization.

=head1 Subroutines

=over 4 

=cut

#############################################
#############################################
package LONCAPA::loncgi;

use strict;
use warnings FATAL=>'all';
no warnings 'uninitialized';

use lib '/home/httpd/lib/perl/';
use CGI();
use CGI::Cookie();
use Fcntl qw(:flock);
use LONCAPA;
use LONCAPA::Configuration();
use GDBM_File;
use Apache::lonlocal;

my $lonidsdir;

BEGIN {
    my $perlvar=LONCAPA::Configuration::read_conf('loncapa.conf');
    delete $perlvar->{'lonReceipt'};
    $lonidsdir = $perlvar->{'lonIDsDir'};
}


#############################################
#############################################

=pod

=item check_cookie_and_load_env()

Inputs: none

Returns: 1 if the user has a LON-CAPA cookie 0 if not.
Loads the users environment into the %env hash if the cookie is correct.

=cut

#############################################
#############################################
sub check_cookie_and_load_env {
    my %cookies=fetch CGI::Cookie;
    if (exists($cookies{'lonID'}) && 
        -e "$lonidsdir/".$cookies{'lonID'}->value.".id") {
        # cookie found
        &transfer_profile_to_env($cookies{'lonID'}->value);
        return 1;
    } else {
        # No cookie found
        return 0;
    }
}

#############################################
#############################################

=pod

=item check_cookie()

Inputs: none

Returns: 1 if the user has a LON-CAPA cookie and 0 if not.

=cut

#############################################
#############################################
sub check_cookie {
    my %cookies=fetch CGI::Cookie;
    if (exists($cookies{'lonID'}) && 
        -e "$lonidsdir/".$cookies{'lonID'}->value.".id") {
        # cookie found
        return 1;
    } else {
        # No cookie found
        return 0;
    }
}

#############################################
#############################################

=pod

=item transfer_profile_to_env()

Load the users environment into the %env hash.

Inputs: $handle, the name of the users LON-CAPA cookie.

Returns: undef

=cut

#############################################
#############################################
sub transfer_profile_to_env {
    my ($handle)=@_;
   if (tie(my %disk_env,'GDBM_File',"$lonidsdir/$handle.id",&GDBM_READER(),
	    0640)) {
	%Apache::lonnet::env = %disk_env;
	untie(%disk_env);
    }
    $Apache::lonnet::env{'user.environment'} = "$lonidsdir/$handle.id";
    return undef;
}

#############################################
#############################################

=pod

=item check_ipbased_access()

Inputs: $page, the identifier of the page to be viewed,
        can be one of the keys in the hash from &serverstatus_titles()

        $ip, the IP address of the client requesting the page.

Returns: 1 if access is permitted for the requestor's IP.
         Access is allowed if on of the following is true:
         (a) the requestor IP is the loopback address
         (b) Domain configurations for domains hosted on this server include
             the requestor's IP as one of the specified IPs with access
             to this page. (does not apply to 'ping' page type) 
=cut

#############################################
#############################################
sub check_ipbased_access {
    my ($page,$ip) = @_;
    my $allowed;
    if (!defined($ip)) {
        $ip = $ENV{'REMOTE_ADDR'};
    }
    if (($page ne 'lonstatus') && ($page ne 'serverstatus')) {
        if ($ip eq '127.0.0.1') {
            $allowed = 1;
            return $allowed;
        }
    }
    if ($page ne 'ping') {
        my @poss_domains = &Apache::lonnet::current_machine_domains();
        foreach my $dom (@poss_domains) {
            my %domconfig = &Apache::lonnet::get_dom('configuration',['serverstatuses'],$dom);
            if (ref($domconfig{'serverstatuses'}) eq 'HASH') {
                if (ref($domconfig{'serverstatuses'}{$page}) eq 'HASH') {
                    if ($domconfig{'serverstatuses'}{$page}{'machines'} ne '') {
                        my @okmachines = split(/,/,$domconfig{'serverstatuses'}{$page}{'machines'});
                        if (grep(/^\Q$ip\E$/,@okmachines)) {
                            $allowed = 1;
                            last;
                        }
                    }
                }
            }
        }
    }
    return $allowed;
}

#############################################
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=pod

=item can_view()

Inputs: $page, the identifier of the page to be viewed,
        can be one of the keys in the hash from &serverstatus_titles()

Returns: 1 if access to the page is permitted.
         Access allowed if one of the following is true:
         (a) Requestor has LON-CAPA superuser role
         (b) Requestor's role is Domain Coordinator in one of the domains
             hosted on this server
         (c) Domain configurations for domains hosted on this server include
             the requestor as one of the named users (username:domain) with access
             to the page.

         In the case of requests for the 'ping' page, and access is also allowed if 
         at least one domain hosted on requestor's server is also hosted on this server.

=cut

#############################################
#############################################
sub can_view {
    my ($page) = @_;
    my $allowed;
    if ($Apache::lonnet::env{'request.role'} =~ m{^su\./}) {
        $allowed = 1;
    } elsif ($page eq 'ping') {
        my @poss_domains = &Apache::lonnet::current_machine_domains();
        my @hostids= &Apache::lonnet::get_hosts_from_ip($ENV{'REMOTE_ADDR'});
        foreach my $hostid (@hostids) { 
            my $hostdom = &Apache::lonnet::host_domain($hostid);
            if (grep(/^\Q$hostdom\E$/,@poss_domains)) {
                $allowed = 1;
                last;
            }
        }
    } else {
        my @poss_domains = &Apache::lonnet::current_machine_domains();
        foreach my $dom (@poss_domains) {
            my %domconfig = &Apache::lonnet::get_dom('configuration',['serverstatuses'],$dom);
            if ($Apache::lonnet::env{'request.role'} eq "dc./$dom/") {
                $allowed = 1;
            } elsif (ref($domconfig{'serverstatuses'}) eq 'HASH') {
                if (ref($domconfig{'serverstatuses'}{$page}) eq 'HASH') {
                    if ($domconfig{'serverstatuses'}{$page}{'namedusers'} ne '') {
                        my @okusers = split(/,/,$domconfig{'serverstatuses'}{$page}{'namedusers'});
                        if (grep(/^\Q$Apache::lonnet::env{'user.name'}:$Apache::lonnet::env{'user.domain'}\E$/,@okusers)) {
                            $allowed = 1;
                        }
                    }
                }
            }
            last if $allowed;
        }
    }
    return $allowed;
}

#############################################
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=pod

=unauthorized_msg()

Inputs: $page, the identifier of the page to be viewed,
        can be one of the keys in the hash from &serverstatus_titles()

Returns: A string explaining why access was denied for the particular page.

=cut

#############################################
#############################################
sub unauthorized_msg {
    my ($page) = @_;
    my $titles = &serverstatus_titles();
    if ($page eq 'clusterstatus') {
        return &mt('Your current role does not permit you to view the requested server status page: [_1]',$titles->{$page});
    }
    my @poss_domains = &Apache::lonnet::current_machine_domains();
    if (@poss_domains == 1) {
        my $domdesc = &Apache::lonnet::domain($poss_domains[0]);
        return &mt('The configuration for domain: [_1] does not permit you to view the requested server status page: [_2].',"$domdesc ($poss_domains[0])",$titles->{$page});
    } elsif (@poss_domains > 1) {
        my $output = &mt('Configurations for the domains housed on this server: ').'<ul>';
        foreach my $dom (@poss_domains) {
            my $domdesc = &Apache::lonnet::domain($dom);
            $output .= '<li>'.&Apache::lonnet::domain($dom).'('.$dom.')</li>';
        }
        $output .= '</ul>'.&mt('do not permit you to view the requested server status page: [_1]',$titles->{$page});
        return $output;
    } else {
        return &mt('No domain information exists for this server');
    }
}

#############################################
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=pod

=item missing_cookie_msg()

Inputs: none
Returns: HTML for a page indicating cookie information absent. 

=cut

#############################################
#############################################
sub missing_cookie_msg {
    my %lt = &Apache::lonlocal::texthash (
                        cook => 'Bad Cookie',
                        your => 'Your cookie information is incorrect.',
             );
    return <<END;
<html>
<head><title>$lt{'cook'}</title></head>
<body>
$lt{'your'}
</body>
</html>
END

}

#############################################
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=pod

=item serverstatus_titles()

Inputs: none

Returns: a reference to a hash of pages, where in the hash
         keys are names of pages which employ loncgi.pm
         or lonstatusacc.pm for access control, 
         and corresponding values are descriptions of each page 

=cut

#############################################
#############################################
sub serverstatus_titles {
    my %titles = &Apache::lonlocal::texthash (
                   'userstatus'        => 'User Status Summary',
                   'lonstatus'         => 'Display Detailed Report',
                   'loncron'           => 'Generate Detailed Report',
                   'server-status'     => 'Apache Status Page',
                   'codeversions'      => 'LON-CAPA Module Versions',
                   'clusterstatus'     => 'Domain status',
                   'metadata_keywords' => 'Display Metadata Keywords',
                   'metadata_harvest'  => 'Harvest Metadata Searches',
                   'takeoffline'       => 'Offline - replace Log-in page',
                   'takeonline'        => 'Online - restore Log-in page',
                   'showenv'           => "Show user environment",
                 );
    return \%titles;
}

#############################################
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=pod

=cgi_getitems()

Inputs: $query (the CGI query string), and $getitems, a reference to a hash 

Returns: nothing

Side Effects: populates $getitems hash ref with key => value
              where each key is the name of the form item in the query string
              and value is an array of corresponding values. 
=cut

#############################################
#############################################
sub cgi_getitems {
    my ($query,$getitems)= @_;
    foreach (split(/&/,$query)) {
        my ($name, $value) = split(/=/,$_);
        $name = &unescape($name);
        $value =~ tr/+/ /;
        $value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
        push(@{$$getitems{$name}},$value);
    }
    return;
}

=pod

=back

=cut

1;

__END__