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1 | # Net::Time.pm |
2 | # |
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3 | # Copyright (c) 1995-2004 Graham Barr <gbarr@pobox.com>. All rights reserved. |
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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 | |
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20 | $VERSION = "2.10"; |
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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 |
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64 | unless defined $s->recv($buf, length(pack("N",0))); |
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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 $buf = ''; |
89 | |
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90 | defined($s->recv($buf, 1024)) ? $buf |
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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); |
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105 | |
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106 | print inet_time(); # use default host from Net::Config |
107 | print inet_time('localhost'); |
108 | print inet_time('localhost', 'tcp'); |
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109 | |
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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 | |
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143 | Copyright (c) 1995-2004 Graham Barr. All rights reserved. |
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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 |