lib/Net/Time.pm

# Net::Time.pm
#
# Copyright (c) 1995-2004 Graham Barr <gbarr@pobox.com>. All rights reserved.
# This program is free software; you can redistribute it and/or
# modify it under the same terms as Perl itself.

package Net::Time;

use strict;
use vars qw($VERSION @ISA @EXPORT_OK $TIMEOUT);
use Carp;
use IO::Socket;
require Exporter;
use Net::Config;
use IO::Select;

@ISA = qw(Exporter);
@EXPORT_OK = qw(inet_time inet_daytime);

$VERSION = "2.10";

$TIMEOUT = 120;

sub _socket
{
 my($pname,$pnum,$host,$proto,$timeout) = @_;

 $proto ||= 'udp';

 my $port = (getservbyname($pname, $proto))[2] || $pnum;

 my $hosts = defined $host ? [ $host ] : $NetConfig{$pname . '_hosts'};

 my $me;

 foreach $host (@$hosts)
  {
   $me = IO::Socket::INET->new(PeerAddr => $host,
                               PeerPort => $port,
                               Proto    => $proto
                              ) and last;
  }

 return unless $me;

 $me->send("\n")
        if $proto eq 'udp';

 $timeout = $TIMEOUT
        unless defined $timeout;

 IO::Select->new($me)->can_read($timeout)
        ? $me
        : undef;
}

sub inet_time
{
 my $s = _socket('time',37,@_) || return undef;
 my $buf = '';
 my $offset = 0 | 0;

 return undef
        unless defined $s->recv($buf, length(pack("N",0)));

 # unpack, we | 0 to ensure we have an unsigned
 my $time = (unpack("N",$buf))[0] | 0;

 # the time protocol return time in seconds since 1900, convert
 # it to a the required format

 if($^O eq "MacOS") {
   # MacOS return seconds since 1904, 1900 was not a leap year.
   $offset = (4 * 31536000) | 0;
 }
 else {
   # otherwise return seconds since 1972, there were 17 leap years between
   # 1900 and 1972
   $offset =  (70 * 31536000 + 17 * 86400) | 0;
 }

 $time - $offset;
}

sub inet_daytime
{
 my $s = _socket('daytime',13,@_) || return undef;
 my $buf = '';

 defined($s->recv($buf, 1024)) ? $buf
                      : undef;
}

1;

__END__

=head1 NAME

Net::Time - time and daytime network client interface

=head1 SYNOPSIS

    use Net::Time qw(inet_time inet_daytime);

    print inet_time();          # use default host from Net::Config
    print inet_time('localhost');
    print inet_time('localhost', 'tcp');

    print inet_daytime();       # use default host from Net::Config
    print inet_daytime('localhost');
    print inet_daytime('localhost', 'tcp');

=head1 DESCRIPTION

C<Net::Time> provides subroutines that obtain the time on a remote machine.

=over 4

=item inet_time ( [HOST [, PROTOCOL [, TIMEOUT]]])

Obtain the time on C<HOST>, or some default host if C<HOST> is not given
or not defined, using the protocol as defined in RFC868. The optional
argument C<PROTOCOL> should define the protocol to use, either C<tcp> or
C<udp>. The result will be a time value in the same units as returned
by time() or I<undef> upon failure.

=item inet_daytime ( [HOST [, PROTOCOL [, TIMEOUT]]])

Obtain the time on C<HOST>, or some default host if C<HOST> is not given
or not defined, using the protocol as defined in RFC867. The optional
argument C<PROTOCOL> should define the protocol to use, either C<tcp> or
C<udp>. The result will be an ASCII string or I<undef> upon failure.

=back

=head1 AUTHOR

Graham Barr <gbarr@pobox.com>

=head1 COPYRIGHT

Copyright (c) 1995-2004 Graham Barr. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.

=cut
Revision:	1.1
Committed:	Thu Jun 30 14:27:14 2005 UTC (21 years, 3 months ago) by root
Branch:	MAIN
CVS Tags:	PERL-5-8-7, HEAD
Branch point for:	PERL
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	# Net::Time.pm
2			#
3			# Copyright (c) 1995-2004 Graham Barr <gbarr@pobox.com>. All rights reserved.
4			# This program is free software; you can redistribute it and/or
5			# modify it under the same terms as Perl itself.
6
7			package Net::Time;
8
9			use strict;
10			use vars qw($VERSION @ISA @EXPORT_OK $TIMEOUT);
11			use Carp;
12			use IO::Socket;
13			require Exporter;
14			use Net::Config;
15			use IO::Select;
16
17			@ISA = qw(Exporter);
18			@EXPORT_OK = qw(inet_time inet_daytime);
19
20			$VERSION = "2.10";
21
22			$TIMEOUT = 120;
23
24			sub _socket
25			{
26			my($pname,$pnum,$host,$proto,$timeout) = @_;
27
28			$proto \|\|= 'udp';
29
30			my $port = (getservbyname($pname, $proto))[2] \|\| $pnum;
31
32			my $hosts = defined $host ? [ $host ] : $NetConfig{$pname . '_hosts'};
33
34			my $me;
35
36			foreach $host (@$hosts)
37			{
38			$me = IO::Socket::INET->new(PeerAddr => $host,
39			PeerPort => $port,
40			Proto => $proto
41			) and last;
42			}
43
44			return unless $me;
45
46			$me->send("\n")
47			if $proto eq 'udp';
48
49			$timeout = $TIMEOUT
50			unless defined $timeout;
51
52			IO::Select->new($me)->can_read($timeout)
53			? $me
54			: undef;
55			}
56
57			sub inet_time
58			{
59			my $s = _socket('time',37,@_) \|\| return undef;
60			my $buf = '';
61			my $offset = 0 \| 0;
62
63			return undef
64			unless defined $s->recv($buf, length(pack("N",0)));
65
66			# unpack, we \| 0 to ensure we have an unsigned
67			my $time = (unpack("N",$buf))[0] \| 0;
68
69			# the time protocol return time in seconds since 1900, convert
70			# it to a the required format
71
72			if($^O eq "MacOS") {
73			# MacOS return seconds since 1904, 1900 was not a leap year.
74			$offset = (4 * 31536000) \| 0;
75			}
76			else {
77			# otherwise return seconds since 1972, there were 17 leap years between
78			# 1900 and 1972
79			$offset = (70 * 31536000 + 17 * 86400) \| 0;
80			}
81
82			$time - $offset;
83			}
84
85			sub inet_daytime
86			{
87			my $s = _socket('daytime',13,@_) \|\| return undef;
88			my $buf = '';
89
90			defined($s->recv($buf, 1024)) ? $buf
91			: undef;
92			}
93
94			1;
95
96			__END__
97
98			=head1 NAME
99
100			Net::Time - time and daytime network client interface
101
102			=head1 SYNOPSIS
103
104			use Net::Time qw(inet_time inet_daytime);
105
106			print inet_time(); # use default host from Net::Config
107			print inet_time('localhost');
108			print inet_time('localhost', 'tcp');
109
110			print inet_daytime(); # use default host from Net::Config
111			print inet_daytime('localhost');
112			print inet_daytime('localhost', 'tcp');
113
114			=head1 DESCRIPTION
115
116			C<Net::Time> provides subroutines that obtain the time on a remote machine.
117
118			=over 4
119
120			=item inet_time ( [HOST [, PROTOCOL [, TIMEOUT]]])
121
122			Obtain the time on C<HOST>, or some default host if C<HOST> is not given
123			or not defined, using the protocol as defined in RFC868. The optional
124			argument C<PROTOCOL> should define the protocol to use, either C<tcp> or
125			C<udp>. The result will be a time value in the same units as returned
126			by time() or I<undef> upon failure.
127
128			=item inet_daytime ( [HOST [, PROTOCOL [, TIMEOUT]]])
129
130			Obtain the time on C<HOST>, or some default host if C<HOST> is not given
131			or not defined, using the protocol as defined in RFC867. The optional
132			argument C<PROTOCOL> should define the protocol to use, either C<tcp> or
133			C<udp>. The result will be an ASCII string or I<undef> upon failure.
134
135			=back
136
137			=head1 AUTHOR
138
139			Graham Barr <gbarr@pobox.com>
140
141			=head1 COPYRIGHT
142
143			Copyright (c) 1995-2004 Graham Barr. All rights reserved.
144			This program is free software; you can redistribute it and/or modify
145			it under the same terms as Perl itself.
146
147			=cut