Commit | Line | Data |
a0d0e21e |
1 | package Sys::Hostname; |
8990e307 |
2 | |
a0d0e21e |
3 | use Carp; |
567d72c2 |
4 | use Config; |
8990e307 |
5 | require Exporter; |
a0d0e21e |
6 | @ISA = qw(Exporter); |
7 | @EXPORT = qw(hostname); |
8990e307 |
8 | |
cb1a09d0 |
9 | =head1 NAME |
10 | |
11 | Sys::Hostname - Try every conceivable way to get hostname |
12 | |
13 | =head1 SYNOPSIS |
14 | |
15 | use Sys::Hostname; |
16 | $host = hostname; |
17 | |
18 | =head1 DESCRIPTION |
19 | |
20 | Attempts several methods of getting the system hostname and |
21 | then caches the result. It tries C<syscall(SYS_gethostname)>, |
22 | C<`hostname`>, C<`uname -n`>, and the file F</com/host>. |
23 | If all that fails it C<croak>s. |
24 | |
25 | All nulls, returns, and newlines are removed from the result. |
26 | |
27 | =head1 AUTHOR |
28 | |
29 | David Sundstrom <sunds@asictest.sc.ti.com> |
30 | |
31 | Texas Instruments |
32 | |
33 | =cut |
8990e307 |
34 | |
35 | sub hostname { |
a0d0e21e |
36 | |
567d72c2 |
37 | # method 1 - we already know it |
38 | return $host if defined $host; |
39 | |
40 | if ($Config{'osname'} eq 'VMS') { |
41 | |
42 | # method 2 - no sockets ==> return DECnet node name |
43 | if (!$Config{'d_has_sockets'}) { return $host = $ENV{'SYS$NODE'}; } |
44 | |
45 | # method 3 - has someone else done the job already? It's common for the |
46 | # TCP/IP stack to advertise the hostname via a logical name. (Are |
47 | # there any other logicals which TCP/IP stacks use for the host name?) |
48 | $host = $ENV{'ARPANET_HOST_NAME'} || $ENV{'INTERNET_HOST_NAME'} || |
49 | $ENV{'MULTINET_HOST_NAME'} || $ENV{'UCX$INET_HOST'} || |
50 | $ENV{'TCPWARE_DOMAINNAME'} || $ENV{'NEWS_ADDRESS'}; |
51 | return $host if $host; |
52 | |
53 | # method 4 - does hostname happen to work? |
54 | my($rslt) = `hostname`; |
55 | if ($rslt !~ /IVVERB/) { ($host) = $rslt =~ /^(\S+)/; } |
56 | return $host if $host; |
57 | |
58 | # rats! |
59 | Carp::croak "Cannot get host name of local machine"; |
60 | |
61 | } |
62 | else { # Unix |
8990e307 |
63 | |
64 | # method 2 - syscall is preferred since it avoids tainting problems |
65 | eval { |
a0d0e21e |
66 | { |
67 | package main; |
68 | require "syscall.ph"; |
69 | } |
8990e307 |
70 | $host = "\0" x 65; ## preload scalar |
a0d0e21e |
71 | syscall(&main::SYS_gethostname, $host, 65) == 0; |
8990e307 |
72 | } |
73 | |
85e6fe83 |
74 | # method 3 - trusty old hostname command |
8990e307 |
75 | || eval { |
a0d0e21e |
76 | $host = `(hostname) 2>/dev/null`; # bsdish |
8990e307 |
77 | } |
78 | |
85e6fe83 |
79 | # method 4 - sysV uname command (may truncate) |
8990e307 |
80 | || eval { |
85e6fe83 |
81 | $host = `uname -n 2>/dev/null`; ## sysVish |
8990e307 |
82 | } |
83 | |
84 | # method 5 - Apollo pre-SR10 |
85 | || eval { |
86 | ($host,$a,$b,$c,$d)=split(/[:\. ]/,`/com/host`,6); |
87 | } |
88 | |
89 | # bummer |
a0d0e21e |
90 | || Carp::croak "Cannot get host name of local machine"; |
8990e307 |
91 | |
92 | # remove garbage |
93 | $host =~ tr/\0\r\n//d; |
94 | $host; |
567d72c2 |
95 | } |
8990e307 |
96 | } |
97 | |
98 | 1; |