| 1 | package Net::hostent; |
| 2 | use strict; |
| 3 | |
| 4 | use 5.006_001; |
| 5 | our $VERSION = '1.00'; |
| 6 | our(@EXPORT, @EXPORT_OK, %EXPORT_TAGS); |
| 7 | BEGIN { |
| 8 | use Exporter (); |
| 9 | @EXPORT = qw(gethostbyname gethostbyaddr gethost); |
| 10 | @EXPORT_OK = qw( |
| 11 | $h_name @h_aliases |
| 12 | $h_addrtype $h_length |
| 13 | @h_addr_list $h_addr |
| 14 | ); |
| 15 | %EXPORT_TAGS = ( FIELDS => [ @EXPORT_OK, @EXPORT ] ); |
| 16 | } |
| 17 | use vars @EXPORT_OK; |
| 18 | |
| 19 | # Class::Struct forbids use of @ISA |
| 20 | sub import { goto &Exporter::import } |
| 21 | |
| 22 | use Class::Struct qw(struct); |
| 23 | struct 'Net::hostent' => [ |
| 24 | name => '$', |
| 25 | aliases => '@', |
| 26 | addrtype => '$', |
| 27 | 'length' => '$', |
| 28 | addr_list => '@', |
| 29 | ]; |
| 30 | |
| 31 | sub addr { shift->addr_list->[0] } |
| 32 | |
| 33 | sub populate (@) { |
| 34 | return unless @_; |
| 35 | my $hob = new(); |
| 36 | $h_name = $hob->[0] = $_[0]; |
| 37 | @h_aliases = @{ $hob->[1] } = split ' ', $_[1]; |
| 38 | $h_addrtype = $hob->[2] = $_[2]; |
| 39 | $h_length = $hob->[3] = $_[3]; |
| 40 | $h_addr = $_[4]; |
| 41 | @h_addr_list = @{ $hob->[4] } = @_[ (4 .. $#_) ]; |
| 42 | return $hob; |
| 43 | } |
| 44 | |
| 45 | sub gethostbyname ($) { populate(CORE::gethostbyname(shift)) } |
| 46 | |
| 47 | sub gethostbyaddr ($;$) { |
| 48 | my ($addr, $addrtype); |
| 49 | $addr = shift; |
| 50 | require Socket unless @_; |
| 51 | $addrtype = @_ ? shift : Socket::AF_INET(); |
| 52 | populate(CORE::gethostbyaddr($addr, $addrtype)) |
| 53 | } |
| 54 | |
| 55 | sub gethost($) { |
| 56 | if ($_[0] =~ /^\d+(?:\.\d+(?:\.\d+(?:\.\d+)?)?)?$/) { |
| 57 | require Socket; |
| 58 | &gethostbyaddr(Socket::inet_aton(shift)); |
| 59 | } else { |
| 60 | &gethostbyname; |
| 61 | } |
| 62 | } |
| 63 | |
| 64 | 1; |
| 65 | __END__ |
| 66 | |
| 67 | =head1 NAME |
| 68 | |
| 69 | Net::hostent - by-name interface to Perl's built-in gethost*() functions |
| 70 | |
| 71 | =head1 SYNOPSIS |
| 72 | |
| 73 | use Net::hostnet; |
| 74 | |
| 75 | =head1 DESCRIPTION |
| 76 | |
| 77 | This module's default exports override the core gethostbyname() and |
| 78 | gethostbyaddr() functions, replacing them with versions that return |
| 79 | "Net::hostent" objects. This object has methods that return the similarly |
| 80 | named structure field name from the C's hostent structure from F<netdb.h>; |
| 81 | namely name, aliases, addrtype, length, and addr_list. The aliases and |
| 82 | addr_list methods return array reference, the rest scalars. The addr |
| 83 | method is equivalent to the zeroth element in the addr_list array |
| 84 | reference. |
| 85 | |
| 86 | You may also import all the structure fields directly into your namespace |
| 87 | as regular variables using the :FIELDS import tag. (Note that this still |
| 88 | overrides your core functions.) Access these fields as variables named |
| 89 | with a preceding C<h_>. Thus, C<$host_obj-E<gt>name()> corresponds to |
| 90 | $h_name if you import the fields. Array references are available as |
| 91 | regular array variables, so for example C<@{ $host_obj-E<gt>aliases() |
| 92 | }> would be simply @h_aliases. |
| 93 | |
| 94 | The gethost() function is a simple front-end that forwards a numeric |
| 95 | argument to gethostbyaddr() by way of Socket::inet_aton, and the rest |
| 96 | to gethostbyname(). |
| 97 | |
| 98 | To access this functionality without the core overrides, |
| 99 | pass the C<use> an empty import list, and then access |
| 100 | function functions with their full qualified names. |
| 101 | On the other hand, the built-ins are still available |
| 102 | via the C<CORE::> pseudo-package. |
| 103 | |
| 104 | =head1 EXAMPLES |
| 105 | |
| 106 | use Net::hostent; |
| 107 | use Socket; |
| 108 | |
| 109 | @ARGV = ('netscape.com') unless @ARGV; |
| 110 | |
| 111 | for $host ( @ARGV ) { |
| 112 | |
| 113 | unless ($h = gethost($host)) { |
| 114 | warn "$0: no such host: $host\n"; |
| 115 | next; |
| 116 | } |
| 117 | |
| 118 | printf "\n%s is %s%s\n", |
| 119 | $host, |
| 120 | lc($h->name) eq lc($host) ? "" : "*really* ", |
| 121 | $h->name; |
| 122 | |
| 123 | print "\taliases are ", join(", ", @{$h->aliases}), "\n" |
| 124 | if @{$h->aliases}; |
| 125 | |
| 126 | if ( @{$h->addr_list} > 1 ) { |
| 127 | my $i; |
| 128 | for $addr ( @{$h->addr_list} ) { |
| 129 | printf "\taddr #%d is [%s]\n", $i++, inet_ntoa($addr); |
| 130 | } |
| 131 | } else { |
| 132 | printf "\taddress is [%s]\n", inet_ntoa($h->addr); |
| 133 | } |
| 134 | |
| 135 | if ($h = gethostbyaddr($h->addr)) { |
| 136 | if (lc($h->name) ne lc($host)) { |
| 137 | printf "\tThat addr reverses to host %s!\n", $h->name; |
| 138 | $host = $h->name; |
| 139 | redo; |
| 140 | } |
| 141 | } |
| 142 | } |
| 143 | |
| 144 | =head1 NOTE |
| 145 | |
| 146 | While this class is currently implemented using the Class::Struct |
| 147 | module to build a struct-like class, you shouldn't rely upon this. |
| 148 | |
| 149 | =head1 AUTHOR |
| 150 | |
| 151 | Tom Christiansen |