1package Net::hostent 1.04; 2use v5.38; 3 4our ( 5 $h_name, @h_aliases, 6 $h_addrtype, $h_length, 7 @h_addr_list, $h_addr 8); 9 10use Exporter 'import'; 11our @EXPORT = qw(gethostbyname gethostbyaddr gethost); 12our @EXPORT_OK = qw( 13 $h_name @h_aliases 14 $h_addrtype $h_length 15 @h_addr_list $h_addr 16 ); 17our %EXPORT_TAGS = ( FIELDS => [ @EXPORT_OK, @EXPORT ] ); 18 19use Class::Struct qw(struct); 20struct 'Net::hostent' => [ 21 name => '$', 22 aliases => '@', 23 addrtype => '$', 24 'length' => '$', 25 addr_list => '@', 26]; 27 28sub addr { shift->addr_list->[0] } 29 30sub populate { 31 return unless @_; 32 my $hob = new(); 33 $h_name = $hob->[0] = $_[0]; 34 @h_aliases = @{ $hob->[1] } = split ' ', $_[1]; 35 $h_addrtype = $hob->[2] = $_[2]; 36 $h_length = $hob->[3] = $_[3]; 37 $h_addr = $_[4]; 38 @h_addr_list = @{ $hob->[4] } = @_[ (4 .. $#_) ]; 39 return $hob; 40} 41 42sub gethostbyname :prototype($) { populate(CORE::gethostbyname(shift)) } 43 44sub gethostbyaddr :prototype($;$) { 45 my ($addr, $addrtype); 46 $addr = shift; 47 require Socket unless @_; 48 $addrtype = @_ ? shift : Socket::AF_INET(); 49 populate(CORE::gethostbyaddr($addr, $addrtype)) 50} 51 52sub gethost :prototype($) { 53 my $addr = shift; 54 if ($addr =~ /^\d+(?:\.\d+(?:\.\d+(?:\.\d+)?)?)?$/) { 55 require Socket; 56 &gethostbyaddr(Socket::inet_aton($addr)); 57 } else { 58 &gethostbyname($addr); 59 } 60} 61 62__END__ 63 64=head1 NAME 65 66Net::hostent - by-name interface to Perl's built-in gethost*() functions 67 68=head1 SYNOPSIS 69 70 use Net::hostent; 71 72=head1 DESCRIPTION 73 74This module's default exports override the core gethostbyname() and 75gethostbyaddr() functions, replacing them with versions that return 76"Net::hostent" objects. This object has methods that return the similarly 77named structure field name from the C's hostent structure from F<netdb.h>; 78namely name, aliases, addrtype, length, and addr_list. The aliases and 79addr_list methods return array reference, the rest scalars. The addr 80method is equivalent to the zeroth element in the addr_list array 81reference. 82 83You may also import all the structure fields directly into your namespace 84as regular variables using the :FIELDS import tag. (Note that this still 85overrides your core functions.) Access these fields as variables named 86with a preceding C<h_>. Thus, C<$host_obj-E<gt>name()> corresponds to 87$h_name if you import the fields. Array references are available as 88regular array variables, so for example C<@{ $host_obj-E<gt>aliases() 89}> would be simply @h_aliases. 90 91The gethost() function is a simple front-end that forwards a numeric 92argument to gethostbyaddr() by way of Socket::inet_aton, and the rest 93to gethostbyname(). 94 95To access this functionality without the core overrides, 96pass the C<use> an empty import list, and then access 97function functions with their full qualified names. 98On the other hand, the built-ins are still available 99via the C<CORE::> pseudo-package. 100 101=head1 EXAMPLES 102 103 use Net::hostent; 104 use Socket; 105 106 @ARGV = ('netscape.com') unless @ARGV; 107 108 for $host ( @ARGV ) { 109 110 unless ($h = gethost($host)) { 111 warn "$0: no such host: $host\n"; 112 next; 113 } 114 115 printf "\n%s is %s%s\n", 116 $host, 117 lc($h->name) eq lc($host) ? "" : "*really* ", 118 $h->name; 119 120 print "\taliases are ", join(", ", @{$h->aliases}), "\n" 121 if @{$h->aliases}; 122 123 if ( @{$h->addr_list} > 1 ) { 124 my $i; 125 for $addr ( @{$h->addr_list} ) { 126 printf "\taddr #%d is [%s]\n", $i++, inet_ntoa($addr); 127 } 128 } else { 129 printf "\taddress is [%s]\n", inet_ntoa($h->addr); 130 } 131 132 if ($h = gethostbyaddr($h->addr)) { 133 if (lc($h->name) ne lc($host)) { 134 printf "\tThat addr reverses to host %s!\n", $h->name; 135 $host = $h->name; 136 redo; 137 } 138 } 139 } 140 141=head1 NOTE 142 143While this class is currently implemented using the Class::Struct 144module to build a struct-like class, you shouldn't rely upon this. 145 146=head1 AUTHOR 147 148Tom Christiansen 149