-# by David Sundstrom sunds@asictest.sc.ti.com
-# Texas Instruments
-
package Sys::Hostname;
use Carp;
@ISA = qw(Exporter);
@EXPORT = qw(hostname);
-#
-# Try every conceivable way to get hostname.
-#
+=head1 NAME
+
+Sys::Hostname - Try every conceivable way to get hostname
+
+=head1 SYNOPSIS
+
+ use Sys::Hostname;
+ $host = hostname;
+
+=head1 DESCRIPTION
+
+Attempts several methods of getting the system hostname and
+then caches the result. It tries C<syscall(SYS_gethostname)>,
+C<`hostname`>, C<`uname -n`>, and the file F</com/host>.
+If all that fails it C<croak>s.
+
+All nulls, returns, and newlines are removed from the result.
+
+=head1 AUTHOR
+
+David Sundstrom E<lt>F<sunds@asictest.sc.ti.com>E<gt>
+
+Texas Instruments
+
+=cut
sub hostname {
- # method 1 - we already know it
- return $host if defined $host;
+ # method 1 - we already know it
+ return $host if defined $host;
+
+ if ($^O eq 'VMS') {
+
+ # method 2 - no sockets ==> return DECnet node name
+ eval { local $SIG{__DIE__}; $host = (gethostbyname('me'))[0] };
+ if ($@) { return $host = $ENV{'SYS$NODE'}; }
+
+ # method 3 - has someone else done the job already? It's common for the
+ # TCP/IP stack to advertise the hostname via a logical name. (Are
+ # there any other logicals which TCP/IP stacks use for the host name?)
+ $host = $ENV{'ARPANET_HOST_NAME'} || $ENV{'INTERNET_HOST_NAME'} ||
+ $ENV{'MULTINET_HOST_NAME'} || $ENV{'UCX$INET_HOST'} ||
+ $ENV{'TCPWARE_DOMAINNAME'} || $ENV{'NEWS_ADDRESS'};
+ return $host if $host;
+
+ # method 4 - does hostname happen to work?
+ my($rslt) = `hostname`;
+ if ($rslt !~ /IVVERB/) { ($host) = $rslt =~ /^(\S+)/; }
+ return $host if $host;
+
+ # rats!
+ $host = '';
+ Carp::croak "Cannot get host name of local machine";
+
+ }
+ elsif ($^O eq 'MSWin32') {
+ ($host) = gethostbyname('localhost');
+ chomp($host = `hostname 2> NUL`) unless defined $host;
+ return $host;
+ }
+ else { # Unix
# method 2 - syscall is preferred since it avoids tainting problems
eval {
+ local $SIG{__DIE__};
{
package main;
require "syscall.ph";
syscall(&main::SYS_gethostname, $host, 65) == 0;
}
+ # method 2a - syscall using systeminfo instead of gethostname
+ # -- needed on systems like Solaris
+ || eval {
+ {
+ package main;
+ require "sys/syscall.ph";
+ require "sys/systeminfo.ph";
+ }
+ $host = "\0" x 65; ## preload scalar
+ syscall(&main::SYS_systeminfo, &main::SI_HOSTNAME, $host, 65) != -1;
+ }
+
# method 3 - trusty old hostname command
|| eval {
+ local $SIG{__DIE__};
$host = `(hostname) 2>/dev/null`; # bsdish
}
# method 4 - sysV uname command (may truncate)
|| eval {
+ local $SIG{__DIE__};
$host = `uname -n 2>/dev/null`; ## sysVish
}
# method 5 - Apollo pre-SR10
|| eval {
+ local $SIG{__DIE__};
($host,$a,$b,$c,$d)=split(/[:\. ]/,`/com/host`,6);
}
# remove garbage
$host =~ tr/\0\r\n//d;
$host;
+ }
}
1;