1package Net::hostent; 2use strict; 3 4use 5.005_64; 5our(@EXPORT, @EXPORT_OK, %EXPORT_TAGS); 6BEGIN { 7 use Exporter (); 8 @EXPORT = qw(gethostbyname gethostbyaddr gethost); 9 @EXPORT_OK = qw( 10 $h_name @h_aliases 11 $h_addrtype $h_length 12 @h_addr_list $h_addr 13 ); 14 %EXPORT_TAGS = ( FIELDS => [ @EXPORT_OK, @EXPORT ] ); 15} 16use vars @EXPORT_OK; 17 18# Class::Struct forbids use of @ISA 19sub import { goto &Exporter::import } 20 21use Class::Struct qw(struct); 22struct 'Net::hostent' => [ 23 name => '$', 24 aliases => '@', 25 addrtype => '$', 26 'length' => '$', 27 addr_list => '@', 28]; 29 30sub addr { shift->addr_list->[0] } 31 32sub populate (@) { 33 return unless @_; 34 my $hob = new(); 35 $h_name = $hob->[0] = $_[0]; 36 @h_aliases = @{ $hob->[1] } = split ' ', $_[1]; 37 $h_addrtype = $hob->[2] = $_[2]; 38 $h_length = $hob->[3] = $_[3]; 39 $h_addr = $_[4]; 40 @h_addr_list = @{ $hob->[4] } = @_[ (4 .. $#_) ]; 41 return $hob; 42} 43 44sub gethostbyname ($) { populate(CORE::gethostbyname(shift)) } 45 46sub gethostbyaddr ($;$) { 47 my ($addr, $addrtype); 48 $addr = shift; 49 require Socket unless @_; 50 $addrtype = @_ ? shift : Socket::AF_INET(); 51 populate(CORE::gethostbyaddr($addr, $addrtype)) 52} 53 54sub gethost($) { 55 if ($_[0] =~ /^\d+(?:\.\d+(?:\.\d+(?:\.\d+)?)?)?$/) { 56 require Socket; 57 &gethostbyaddr(Socket::inet_aton(shift)); 58 } else { 59 &gethostbyname; 60 } 61} 62 631; 64__END__ 65 66=head1 NAME 67 68Net::hostent - by-name interface to Perl's built-in gethost*() functions 69 70=head1 SYNOPSIS 71 72 use Net::hostnet; 73 74=head1 DESCRIPTION 75 76This module's default exports override the core gethostbyname() and 77gethostbyaddr() functions, replacing them with versions that return 78"Net::hostent" objects. This object has methods that return the similarly 79named structure field name from the C's hostent structure from F<netdb.h>; 80namely name, aliases, addrtype, length, and addr_list. The aliases and 81addr_list methods return array reference, the rest scalars. The addr 82method is equivalent to the zeroth element in the addr_list array 83reference. 84 85You may also import all the structure fields directly into your namespace 86as regular variables using the :FIELDS import tag. (Note that this still 87overrides your core functions.) Access these fields as variables named 88with a preceding C<h_>. Thus, C<$host_obj-E<gt>name()> corresponds to 89$h_name if you import the fields. Array references are available as 90regular array variables, so for example C<@{ $host_obj-E<gt>aliases() 91}> would be simply @h_aliases. 92 93The gethost() function is a simple front-end that forwards a numeric 94argument to gethostbyaddr() by way of Socket::inet_aton, and the rest 95to gethostbyname(). 96 97To access this functionality without the core overrides, 98pass the C<use> an empty import list, and then access 99function functions with their full qualified names. 100On the other hand, the built-ins are still available 101via the C<CORE::> pseudo-package. 102 103=head1 EXAMPLES 104 105 use Net::hostent; 106 use Socket; 107 108 @ARGV = ('netscape.com') unless @ARGV; 109 110 for $host ( @ARGV ) { 111 112 unless ($h = gethost($host)) { 113 warn "$0: no such host: $host\n"; 114 next; 115 } 116 117 printf "\n%s is %s%s\n", 118 $host, 119 lc($h->name) eq lc($host) ? "" : "*really* ", 120 $h->name; 121 122 print "\taliases are ", join(", ", @{$h->aliases}), "\n" 123 if @{$h->aliases}; 124 125 if ( @{$h->addr_list} > 1 ) { 126 my $i; 127 for $addr ( @{$h->addr_list} ) { 128 printf "\taddr #%d is [%s]\n", $i++, inet_ntoa($addr); 129 } 130 } else { 131 printf "\taddress is [%s]\n", inet_ntoa($h->addr); 132 } 133 134 if ($h = gethostbyaddr($h->addr)) { 135 if (lc($h->name) ne lc($host)) { 136 printf "\tThat addr reverses to host %s!\n", $h->name; 137 $host = $h->name; 138 redo; 139 } 140 } 141 } 142 143=head1 NOTE 144 145While this class is currently implemented using the Class::Struct 146module to build a struct-like class, you shouldn't rely upon this. 147 148=head1 AUTHOR 149 150Tom Christiansen 151