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package Discover; # $Id$ |
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|
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################################################################################ |
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# Part of Mageia Online # |
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# Online service discovery library: # |
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# - autodetects nameservers and domains, # |
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# - and checks for DNS-declared Online service, # |
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# # |
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# Check http://www.dns-sd.org/ # |
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# # |
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# Copyright (C) 2005 Mandriva # |
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# # |
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# Romain d'Alverny <rdalverny at mandriva dot com> # |
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# # |
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# This program is free software; you can redistribute it and/or modify # |
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# it under the terms of the GNU General Public License Version 2 as # |
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# published by the Free Software Foundation. # |
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# # |
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# This program is distributed in the hope that it will be useful, # |
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# but WITHOUT ANY WARRANTY; without even the implied warranty of # |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # |
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# GNU General Public License for more details. # |
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# # |
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# You should have received a copy of the GNU General Public License # |
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# along with this program; if not, write to the Free Software # |
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# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. # |
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################################################################################ |
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|
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use strict; |
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use Net::DNS; |
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use Data::Dumper; |
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use MDK::Common; |
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use Config::Auto; # CPAN Module. Seems not to be part of Mageia packages yet. |
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use Switch; |
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|
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use Log::Agent; # use settings from main file |
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|
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my $VERSION = '0.01'; |
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|
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# |
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sub new { |
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my $self = {}; |
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bless $self, "Discover"; |
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logsay "DNS Service Discovery module $VERSION"; |
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return $self; |
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} |
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|
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# |
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sub init { |
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my $this = shift; |
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$this->{domainname} = ''; |
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$this->{zone} = ''; |
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$this->{service} = ''; |
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$this->{nameserver} = ''; |
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$this->{instance} = ''; |
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} |
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|
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# |
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sub commify_series { |
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(@_ == 0) ? '' : |
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(@_ == 1) ? $_[0] : |
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(@_ == 2) ? join(" and ", @_) : |
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join(", ", @_[0 .. ($#_-1)], "and $_[-1]"); |
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} |
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|
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# |
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sub search { |
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my $this = shift; |
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|
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logsay "searching for a locally declared Mageia Online service"; |
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|
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my $resolv = Config::Auto::parse('/etc/resolv.conf'); |
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my $servicetype = '_mdvonline._http._tcp.bonjour.'; |
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my (@domains, @services); |
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|
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! defined $resolv and logerr "No config found from /etc/resolv.conf.", return 0; |
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|
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defined $resolv->{domain} and @domains = $resolv->{domain}; |
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defined $resolv->{search} and push @domains, @{$resolv->{search}}; |
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|
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@domains = uniq(@domains); |
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for my $domain ( @domains ) { |
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push( @services, $servicetype . $domain ); |
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} |
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logsay "found domains: " . commify_series(@domains); |
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logsay "found nameservers: " . commify_series(@{$resolv->{nameserver}}); |
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|
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# for dev. |
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@{$resolv->{nameserver}} = qw(localhost); |
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|
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# will try each nameserver listed |
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foreach my $ns ( @{$resolv->{nameserver}} ) { |
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# for each possible service/domain |
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foreach my $serv ( @services ) { |
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logsay "trying ns $ns, service $serv"; |
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my $ret = $this->find_service( $ns, $serv ); |
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|
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$ret and logsay "service found", return $ret; |
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} |
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} |
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logwarn "no dns-declared service found"; |
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return 0; |
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}; |
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|
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# NOTE. here it is suppposed that for a given Service instance (PTR), |
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# there is only _one_ SRV record and _one_ TXT record matches. |
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# If there are more, no particular behaviour is expected as for now. |
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# NOTE. replace this code with a wrapper around dig? |
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sub find_service { |
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my ($this, $nameserver, $service) = @_; |
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my $return; |
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|
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# lower the values to make it faster to give up |
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my $retry = 2; # default is 120 |
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my $retrans = 2; # default is 5 |
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logsay "retry rate is set to $retry; retrans rate is set to $retrans"; |
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my $res = Net::DNS::Resolver->new( |
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retry => $retry, |
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retrans => $retrans, |
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#debug => 1 |
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); |
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|
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# TODO make sure the nameserver answers, or set a timeout. |
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$res->nameservers( $nameserver ); |
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|
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# 1. search for any PTR record matching the service name |
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logsay "ns $nameserver: PTR $service ?"; |
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my $query = $res->query( $service, 'PTR' ); |
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my $instanceName; |
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if( $query ) { |
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# TODO better parsing of the struct |
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my $rr = $query->{answer}[0]; |
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|
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! defined $rr and logerr "not expected format found in PTR record.", return 0; |
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|
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$instanceName = $rr->ptrdname; |
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$instanceName =~ s/\\032/ /g; |
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logsay "found '$instanceName'"; |
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$this->{serviceInstanceName} = $instanceName; |
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} |
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else { |
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logwarn "no PTR record found."; |
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logwarn $res->errorstring; |
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return 0; |
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} |
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|
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# 2. for each service instance found, look up for SRV/TXT records. |
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logsay "ns $nameserver: SRV '$instanceName' ?"; |
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$query = $res->query( $instanceName, 'SRV' ); |
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if( $query ) { |
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my $rr = $query->{answer}[0]; |
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logsay "yes: " . $rr->target . ":" . $rr->port; |
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$this->{server} = { priority => $rr->priority, weight => $rr->weight, |
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port => $rr->port, host => $rr->target }; |
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$return->{server} = $this->{server}; |
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} |
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else { |
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logwarn "no matching SRV record found."; |
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logwarn $res->errorstring; |
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return 0; |
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} |
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|
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logsay "ns $nameserver: TXT '$instanceName' ?"; |
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$query = $res->query( $instanceName, 'TXT' ); |
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if( $query ) { |
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my $rr = $query->{answer}[0]; |
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logsay "yes: " . join(', ', $rr->char_str_list() ); |
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$return->{config} = $this->parse_txt_config( $rr->char_str_list() ); |
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! defined $return->{config} and logwarn "But no config found.", return 0; |
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} |
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else { |
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logwarn "No matching TXT record found."; |
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logwarn $res->errorstring; |
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return 0; |
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} |
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return $return; |
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}; |
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|
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# translate the txt record* into a properly formatted hash. |
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# |
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# * consists of a list of 'key=value' strings; handled strings are: |
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# txtvers=n (integer) |
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# conf=a,b (string: name of the config,integer: set time) |
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# update=p (string: path to update server) |
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# service=s (string: path to service resource) |
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# user=s (string: default user name to use) |
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# pass=s (string: default password to use) |
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# auto=b (TRUE|FALSE: whether to act automatically or not) |
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# mobile=b (TRUE|FALSE: whether to act as a mobile agent or not) |
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# |
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sub parse_txt_config { |
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my ($this, @config) = @_; |
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my $retconfig; |
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|
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foreach my $line (@config) { |
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# TODO match these with a regexp |
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my @line = split('=', $line); |
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my $key = shift(@line); |
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my $value = join('=', @line); |
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switch ($key) { |
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case 'txtvers' { $retconfig->{txtvers} = $value; } |
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case 'conf' { |
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my @co = split(',', $value); |
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$retconfig->{conf} = { 'name' => $co[0], 'time' => $co[1] }; |
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} |
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case 'update' { $retconfig->{update} = $value; } |
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case 'service' { $retconfig->{service} = $value; } |
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case 'user' { $retconfig->{user} = $value; } |
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case 'pass' { $retconfig->{pass} = $value; } |
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case 'auto' { $retconfig->{auto} = 1; } |
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case 'mobile' { $retconfig->{mobile} = 1; } |
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else {} |
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} |
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} |
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$this->{config} = $retconfig; |
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return $retconfig; |
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}; |
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|
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