lib/perl5/5.6.1/msys/Sys/Hostname.pm

   1 package Sys::Hostname;
   2
   3 use strict;
   4
   5 use Carp;
   6
   7 require Exporter;
   8 use XSLoader ();
   9 require AutoLoader;
  10
  11 our @ISA     = qw/ Exporter AutoLoader /;
  12 our @EXPORT  = qw/ hostname /;
  13
  14 our $VERSION = '1.1';
  15
  16 our $host;
  17
  18 XSLoader::load 'Sys::Hostname', $VERSION;
  19
  20 sub hostname {
  21
  22   # method 1 - we already know it
  23   return $host if defined $host;
  24
  25   # method 1' - try to ask the system
  26   $host = ghname();
  27   return $host if defined $host;
  28
  29   if ($^O eq 'VMS') {
  30
  31     # method 2 - no sockets ==> return DECnet node name
  32     eval { local $SIG{__DIE__}; $host = (gethostbyname('me'))[0] };
  33     if ($@) { return $host = $ENV{'SYS$NODE'}; }
  34
  35     # method 3 - has someone else done the job already?  It's common for the
  36     #    TCP/IP stack to advertise the hostname via a logical name.  (Are
  37     #    there any other logicals which TCP/IP stacks use for the host name?)
  38     $host = $ENV{'ARPANET_HOST_NAME'}  || $ENV{'INTERNET_HOST_NAME'} ||
  39             $ENV{'MULTINET_HOST_NAME'} || $ENV{'UCX$INET_HOST'}      ||
  40             $ENV{'TCPWARE_DOMAINNAME'} || $ENV{'NEWS_ADDRESS'};
  41     return $host if $host;
  42
  43     # method 4 - does hostname happen to work?
  44     my($rslt) = `hostname`;
  45     if ($rslt !~ /IVVERB/) { ($host) = $rslt =~ /^(\S+)/; }
  46     return $host if $host;
  47
  48     # rats!
  49     $host = '';
  50     Carp::croak "Cannot get host name of local machine";
  51
  52   }
  53   elsif ($^O eq 'MSWin32') {
  54     ($host) = gethostbyname('localhost');
  55     chomp($host = `hostname 2> NUL`) unless defined $host;
  56     return $host;
  57   }
  58   elsif ($^O eq 'epoc') {
  59     $host = 'localhost';
  60     return $host;
  61   }
  62   else {  # Unix
  63     # is anyone going to make it here?
  64
  65     # method 2 - syscall is preferred since it avoids tainting problems
  66     # XXX: is it such a good idea to return hostname untainted?
  67     eval {
  68         local $SIG{__DIE__};
  69         require "syscall.ph";
  70         $host = "\0" x 65; ## preload scalar
  71         syscall(&SYS_gethostname, $host, 65) == 0;
  72     }
  73
  74     # method 2a - syscall using systeminfo instead of gethostname
  75     #           -- needed on systems like Solaris
  76     || eval {
  77         local $SIG{__DIE__};
  78         require "sys/syscall.ph";
  79         require "sys/systeminfo.ph";
  80         $host = "\0" x 65; ## preload scalar
  81         syscall(&SYS_systeminfo, &SI_HOSTNAME, $host, 65) != -1;
  82     }
  83
  84     # method 3 - trusty old hostname command
  85     || eval {
  86         local $SIG{__DIE__};
  87         local $SIG{CHLD};
  88         $host = `(hostname) 2>/dev/null`; # bsdish
  89     }
  90
  91     # method 4 - use POSIX::uname(), which strictly can't be expected to be
  92     # correct
  93     || eval {
  94         local $SIG{__DIE__};
  95         require POSIX;
  96         $host = (POSIX::uname())[1];
  97     }
  98
  99     # method 5 - sysV uname command (may truncate)
 100     || eval {
 101         local $SIG{__DIE__};
 102         $host = `uname -n 2>/dev/null`; ## sysVish
 103     }
 104
 105     # method 6 - Apollo pre-SR10
 106     || eval {
 107         local $SIG{__DIE__};
 108         my($a,$b,$c,$d);
 109         ($host,$a,$b,$c,$d)=split(/[:\. ]/,`/com/host`,6);
 110     }
 111
 112     # bummer
 113     || Carp::croak "Cannot get host name of local machine";
 114
 115     # remove garbage
 116     $host =~ tr/\0\r\n//d;
 117     $host;
 118   }
 119 }
 120
 121 1;
 122
 123 __END__
 124
 125 =head1 NAME
 126
 127 Sys::Hostname - Try every conceivable way to get hostname
 128
 129 =head1 SYNOPSIS
 130
 131     use Sys::Hostname;
 132     $host = hostname;
 133
 134 =head1 DESCRIPTION
 135
 136 Attempts several methods of getting the system hostname and
 137 then caches the result.  It tries the first available of the C
 138 library's gethostname(), C<`$Config{aphostname}`>, uname(2),
 139 C<syscall(SYS_gethostname)>, C<`hostname`>, C<`uname -n`>,
 140 and the file F</com/host>.  If all that fails it C<croak>s.
 141
 142 All NULs, returns, and newlines are removed from the result.
 143
 144 =head1 AUTHOR
 145
 146 David Sundstrom E<lt>F<sunds@asictest.sc.ti.com>E<gt>
 147
 148 Texas Instruments
 149
 150 XS code added by Greg Bacon E<lt>F<gbacon@cs.uah.edu>E<gt>
 151
 152 =cut
 153