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1 | package Net::hostent; |
2 | use strict; |
3 | |
4 | BEGIN { |
5 | use Exporter (); |
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6 | use vars qw(@EXPORT @EXPORT_OK %EXPORT_TAGS); |
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7 | @EXPORT = qw(gethostbyname gethostbyaddr gethost); |
8 | @EXPORT_OK = qw( |
9 | $h_name @h_aliases |
10 | $h_addrtype $h_length |
11 | @h_addr_list $h_addr |
12 | ); |
13 | %EXPORT_TAGS = ( FIELDS => [ @EXPORT_OK, @EXPORT ] ); |
14 | } |
15 | use vars @EXPORT_OK; |
16 | |
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17 | # Class::Struct forbids use of @ISA |
18 | sub import { goto &Exporter::import } |
19 | |
20 | use Class::Struct qw(struct); |
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21 | struct 'Net::hostent' => [ |
22 | name => '$', |
23 | aliases => '@', |
24 | addrtype => '$', |
25 | 'length' => '$', |
26 | addr_list => '@', |
27 | ]; |
28 | |
29 | sub addr { shift->addr_list->[0] } |
30 | |
31 | sub populate (@) { |
32 | return unless @_; |
33 | my $hob = new(); |
34 | $h_name = $hob->[0] = $_[0]; |
35 | @h_aliases = @{ $hob->[1] } = split ' ', $_[1]; |
36 | $h_addrtype = $hob->[2] = $_[2]; |
37 | $h_length = $hob->[3] = $_[3]; |
38 | $h_addr = $_[4]; |
39 | @h_addr_list = @{ $hob->[4] } = @_[ (4 .. $#_) ]; |
40 | return $hob; |
41 | } |
42 | |
43 | sub gethostbyname ($) { populate(CORE::gethostbyname(shift)) } |
44 | |
45 | sub gethostbyaddr ($;$) { |
46 | my ($addr, $addrtype); |
47 | $addr = shift; |
48 | require Socket unless @_; |
49 | $addrtype = @_ ? shift : Socket::AF_INET(); |
50 | populate(CORE::gethostbyaddr($addr, $addrtype)) |
51 | } |
52 | |
53 | sub gethost($) { |
54 | if ($_[0] =~ /^\d+(?:\.\d+(?:\.\d+(?:\.\d+)?)?)?$/) { |
55 | require Socket; |
56 | &gethostbyaddr(Socket::inet_aton(shift)); |
57 | } else { |
58 | &gethostbyname; |
59 | } |
60 | } |
61 | |
62 | 1; |
63 | __END__ |
64 | |
65 | =head1 NAME |
66 | |
67 | Net::hostent - by-name interface to Perl's built-in gethost*() functions |
68 | |
69 | =head1 SYNOPSIS |
70 | |
71 | use Net::hostnet; |
72 | |
73 | =head1 DESCRIPTION |
74 | |
75 | This module's default exports override the core gethostbyname() and |
76 | gethostbyaddr() functions, replacing them with versions that return |
77 | "Net::hostent" objects. This object has methods that return the similarly |
78 | named structure field name from the C's hostent structure from F<netdb.h>; |
79 | namely name, aliases, addrtype, length, and addresses. The aliases and |
80 | addresses methods return array reference, the rest scalars. The addr |
81 | method is equivalent to the zeroth element in the addresses array |
82 | reference. |
83 | |
84 | You may also import all the structure fields directly into your namespace |
85 | as regular variables using the :FIELDS import tag. (Note that this still |
86 | overrides your core functions.) Access these fields as variables named |
87 | with a preceding C<h_>. Thus, C<$host_obj-E<gt>name()> corresponds to |
88 | $h_name if you import the fields. Array references are available as |
89 | regular array variables, so for example C<@{ $host_obj-E<gt>aliases() |
90 | }> would be simply @h_aliases. |
91 | |
92 | The gethost() funtion is a simple front-end that forwards a numeric |
93 | argument to gethostbyaddr() by way of Socket::inet_aton, and the rest |
94 | to gethostbyname(). |
95 | |
96 | To access this functionality without the core overrides, |
97 | pass the C<use> an empty import list, and then access |
98 | function functions with their full qualified names. |
99 | On the other hand, the built-ins are still available |
100 | via the C<CORE::> pseudo-package. |
101 | |
102 | =head1 EXAMPLES |
103 | |
104 | use Net::hostent; |
105 | use Socket; |
106 | |
107 | @ARGV = ('netscape.com') unless @ARGV; |
108 | |
109 | for $host ( @ARGV ) { |
110 | |
111 | unless ($h = gethost($host)) { |
112 | warn "$0: no such host: $host\n"; |
113 | next; |
114 | } |
115 | |
116 | printf "\n%s is %s%s\n", |
117 | $host, |
118 | lc($h->name) eq lc($host) ? "" : "*really* ", |
119 | $h->name; |
120 | |
121 | print "\taliases are ", join(", ", @{$h->aliases}), "\n" |
122 | if @{$h->aliases}; |
123 | |
124 | if ( @{$h->addr_list} > 1 ) { |
125 | my $i; |
126 | for $addr ( @{$h->addr_list} ) { |
127 | printf "\taddr #%d is [%s]\n", $i++, inet_ntoa($addr); |
128 | } |
129 | } else { |
130 | printf "\taddress is [%s]\n", inet_ntoa($h->addr); |
131 | } |
132 | |
133 | if ($h = gethostbyaddr($h->addr)) { |
134 | if (lc($h->name) ne lc($host)) { |
135 | printf "\tThat addr reverses to host %s!\n", $h->name; |
136 | $host = $h->name; |
137 | redo; |
138 | } |
139 | } |
140 | } |
141 | |
142 | =head1 NOTE |
143 | |
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144 | While this class is currently implemented using the Class::Struct |
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145 | module to build a struct-like class, you shouldn't rely upon this. |
146 | |
147 | =head1 AUTHOR |
148 | |
149 | Tom Christiansen |