package Net::DNS::Resolver::os390;

#

# $Id: os390.pm 1579 2017-06-26 11:36:57Z willem $

#

our $VERSION = (qw$LastChangedRevision: 1579 $)[1];

=head1 NAME

Net::DNS::Resolver::os390 - IBM OS/390 resolver class

=cut

use strict;

use warnings;

use base qw(Net::DNS::Resolver::Base);

local $ENV{PATH} = '/bin:/usr/bin';

my $sysname = eval {`sysvar SYSNAME 2>/dev/null`} || '';

chomp $sysname;

my %RESOLVER_SETUP;			## placeholders for unimplemented search list elements

my @dataset = (				## plausible places to seek resolver configuration

	$RESOLVER_SETUP{GLOBALTCPIPDATA},

	$ENV{RESOLVER_CONFIG},					# MVS dataset or Unix file name

	"/etc/resolv.conf",

	$RESOLVER_SETUP{SYSTCPD},

	"//TCPIP.DATA",						# <username>.TCPIP.DATA

	"//'${sysname}.TCPPARMS(TCPDATA)'",

	"//'SYS1.TCPPARMS(TCPDATA)'",

	$RESOLVER_SETUP{DEFAULTTCPIPDATA},

	"//'TCPIP.TCPIP.DATA'"

	);

my $dotfile = '.resolv.conf';

my @dotpath = grep defined, $ENV{HOME}, '.';

my @dotfile = grep -f $_ && -o _, map "$_/$dotfile", @dotpath;

my %option = (				## map MVS config option names

	NSPORTADDR	   => 'port',

	RESOLVERTIMEOUT	   => 'retrans',

	RESOLVERUDPRETRIES => 'retry',

	SORTLIST	   => 'sortlist',

	);

sub _init {

	my $defaults = shift->_defaults;

	my %stop;

	local $ENV{PATH} = '/bin:/usr/bin';

	foreach my $dataset ( Net::DNS::Resolver::Base::_untaint( grep defined, @dataset ) ) {

		eval {

			local *FILE;				# "cat" able to read MVS dataset

			open( FILE, qq[cat "$dataset" 2>/dev/null |] ) or die "$dataset: $!";

			my @nameserver;

			my @searchlist;

			local $_;

			while (<FILE>) {

				s/[;#].*$//;			# strip comment

				s/^\s+//;			# strip leading white space

				next unless $_;			# skip empty line

				next if m/^\w+:/ && !m/^$sysname:/oi;

				s/^\w+:\s*//;			# discard qualifier

				m/^(NSINTERADDR|nameserver)/i && do {

					my ( $keyword, @ip ) = grep defined, split;

					push @nameserver, @ip;

					next;

				};

				m/^(DOMAINORIGIN|domain)/i && do {

					my ( $keyword, @domain ) = grep defined, split;

					$defaults->domain(@domain) unless $stop{domain}++;

					next;

				};

				m/^search/i && do {

					my ( $keyword, @domain ) = grep defined, split;

					push @searchlist, @domain;

					next;

				};

				m/^option/i && do {

					my ( $keyword, @option ) = grep defined, split;

					foreach (@option) {

						my ( $attribute, @value ) = split m/:/;

						$defaults->_option( $attribute, @value )

								unless $stop{$attribute}++;

					}

					next;

				};

				m/^RESOLVEVIA/i && do {

					my ( $keyword, $value ) = grep defined, split;

					$defaults->_option( 'usevc', $value eq 'TCP' )

							unless $stop{usevc}++;

					next;

				};

				m/^\w+\s*/ && do {

					my ( $keyword, @value ) = grep defined, split;

					my $attribute = $option{uc $keyword} || next;

					$defaults->_option( $attribute, @value )

							unless $stop{$attribute}++;

				};

			}

			close(FILE);

			$defaults->nameserver(@nameserver) if @nameserver && !$stop{nameserver}++;

			$defaults->searchlist(@searchlist) if @searchlist && !$stop{search}++;

		};

		warn $@ if $@;

	}

	%$defaults = Net::DNS::Resolver::Base::_untaint(%$defaults);

	map $defaults->_read_config_file($_), @dotfile;

	$defaults->_read_env;

}

1;

__END__

=head1 SYNOPSIS

    use Net::DNS::Resolver;

=head1 DESCRIPTION

This class implements the OS specific portions of C<Net::DNS::Resolver>.

No user serviceable parts inside, see L<Net::DNS::Resolver>

for all your resolving needs.

=head1 COPYRIGHT

Copyright (c)2017 Dick Franks.

All rights reserved.

=head1 LICENSE

Permission to use, copy, modify, and distribute this software and its

documentation for any purpose and without fee is hereby granted, provided

that the above copyright notice appear in all copies and that both that

copyright notice and this permission notice appear in supporting

documentation, and that the name of the author not be used in advertising

or publicity pertaining to distribution of the software without specific

prior written permission.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

DEALINGS IN THE SOFTWARE.

=head1 SEE ALSO

L<perl>, L<Net::DNS>, L<Net::DNS::Resolver>

=cut