server.cgi

   1 #!/usr/bin/perl
   2 #
   3 # Copyright (c) 2013 Michel Ketterle, Steven Schubiger
   4 #
   5 # This file is part of distdns.
   6 #
   7 # distdns is free software: you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation, either version 3 of the License, or
  10 # (at your option) any later version.
  11 #
  12 # distdns is distributed in the hope that it will be useful,
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 # GNU General Public License for more details.
  16 #
  17 # You should have received a copy of the GNU General Public License
  18 # along with distdns.  If not, see <http://www.gnu.org/licenses/>.
  19
  20 use strict;
  21 use warnings;
  22 use lib qw(lib);
  23
  24 use CGI ();
  25 use Config::Tiny ();
  26 use Fcntl ':flock';
  27 use File::Spec::Functions qw(catfile rel2abs);
  28 use FindBin qw($Bin);
  29 use JSON qw(decode_json encode_json);
  30
  31 my $VERSION = '0.05';
  32
  33 my $conf_file = catfile($Bin, 'server.conf');
  34
  35 my $query = CGI->new;
  36
  37 my @params = qw(netz pc name debug init session);
  38 my %params;
  39
  40 foreach my $param (@params) {
  41     $params{$param} = $query->param($param);
  42 }
  43 $params{ip} = $query->remote_addr;
  44
  45 if ($params{debug}) {
  46     $SIG{__DIE__} = sub
  47     {
  48         print $query->header('application/json');
  49         print encode_json({ entries => [], error => $_[0] });
  50         exit;
  51     };
  52 }
  53
  54 my $config = Config::Tiny->new;
  55    $config = Config::Tiny->read($conf_file);
  56
  57 my $section = 'path';
  58
  59 die "Section $section missing in $conf_file\n" unless exists $config->{$section};
  60
  61 my @options = qw(json_file session_file);
  62
  63 my %options;
  64 @options{@options} = @{$config->{$section}}{@options};
  65
  66 foreach my $option (@options) {
  67     die "Option $option not set in $conf_file\n" unless defined $options{$option} && length $options{$option};
  68 }
  69
  70 my ($json_file, $session_file) = map rel2abs($options{$_}, $Bin), @options;
  71
  72 if ($params{init}) {
  73     die "Delete $session_file first\n" if -e $session_file;
  74
  75     open(my $fh, '>', $session_file) or die "Cannot open $session_file for writing: $!\n";
  76     print {$fh} "$params{session}\n";
  77     close($fh);
  78 }
  79 else {
  80     open(my $fh, '<', $session_file) or die "Cannot open $session_file for reading: $!\nPerhaps try running --init\n";
  81     my $session = do { local $/; <$fh> };
  82     chomp $session;
  83     close($fh);
  84
  85     die "Session ID mismatch\n" unless $params{session} eq $session;
  86 }
  87
  88 my @missing_params = grep { not defined $params{$_} && length $params{$_} } @params;
  89 if (@missing_params) {
  90     my $missing_params = join ', ', map "'$_'", @missing_params;
  91     die "Incomplete query: param(s) $missing_params missing or not defined\n";
  92 }
  93
  94 my %access;
  95 my $access_file = "$params{netz}.conf";
  96
  97 if (-e $access_file) {
  98     open(my $fh, '<', $access_file) or die "Cannot open $access_file for reading: $!\n";
  99     while (my $line = <$fh>) {
 100         chomp $line;
 101         my ($name, $pc) = split /\s*,\s*/, $line;
 102         push @{$access{$name}}, $pc;
 103     }
 104     close($fh);
 105 }
 106 else {
 107     die "Access file $access_file does not exist\n";
 108 }
 109
 110 if (exists $access{$params{name}} && grep /^$params{pc}$/i, @{$access{$params{name}}}) {
 111     open(my $fh, '+<', $json_file) or die "Cannot open $json_file for read/write: $!\n";
 112     flock($fh, LOCK_EX)            or die "Cannot lock $json_file: $!\n";
 113
 114     my $json = do { local $/; <$fh> };
 115
 116     my $data = defined $json && length $json ? decode_json($json) : [];
 117
 118     for (my $i = 0; $i < @$data; $i++) {
 119         if ($params{netz} eq $data->[$i]->{netz}
 120          && $params{pc}   eq $data->[$i]->{pc}
 121          && $params{name} eq $data->[$i]->{name}) {
 122             splice @$data, $i--, 1;
 123         }
 124     }
 125     push @$data, { map { $_ => $params{$_} } qw(netz pc name ip) };
 126
 127     seek($fh, 0, 0)  or die "Cannot seek to start of $json_file: $!\n";
 128     truncate($fh, 0) or die "Cannot truncate $json_file: $!\n";
 129
 130     print {$fh} encode_json($data);
 131
 132     close($fh);
 133
 134     my @data = grep $_->{netz} eq $params{netz}, @$data;
 135
 136     print $query->header('application/json');
 137     print encode_json({ entries => \@data, error => undef });
 138 }
 139 else {
 140     die "Access not permitted\n";
 141 }