Commit | Line | Data |
406c51ee |
1 | # Net::Domain.pm |
2 | # |
3 | # Copyright (c) 1995-1998 Graham Barr <gbarr@pobox.com>. All rights reserved. |
4 | # This program is free software; you can redistribute it and/or |
5 | # modify it under the same terms as Perl itself. |
6 | |
7 | package Net::Domain; |
8 | |
9 | require Exporter; |
10 | |
11 | use Carp; |
12 | use strict; |
13 | use vars qw($VERSION @ISA @EXPORT_OK); |
14 | use Net::Config; |
15 | |
b3f6f6a6 |
16 | @ISA = qw(Exporter); |
406c51ee |
17 | @EXPORT_OK = qw(hostname hostdomain hostfqdn domainname); |
18 | |
b3f6f6a6 |
19 | $VERSION = "2.20"; |
406c51ee |
20 | |
b3f6f6a6 |
21 | my ($host, $domain, $fqdn) = (undef, undef, undef); |
406c51ee |
22 | |
23 | # Try every conceivable way to get hostname. |
24 | |
b3f6f6a6 |
25 | |
406c51ee |
26 | sub _hostname { |
27 | |
b3f6f6a6 |
28 | # we already know it |
29 | return $host |
30 | if (defined $host); |
31 | |
32 | if ($^O eq 'MSWin32') { |
33 | require Socket; |
34 | my ($name, $alias, $type, $len, @addr) = gethostbyname($ENV{'COMPUTERNAME'} || 'localhost'); |
35 | while (@addr) { |
36 | my $a = shift(@addr); |
37 | $host = gethostbyaddr($a, Socket::AF_INET()); |
38 | last if defined $host; |
406c51ee |
39 | } |
b3f6f6a6 |
40 | if (defined($host) && index($host, '.') > 0) { |
41 | $fqdn = $host; |
42 | ($host, $domain) = $fqdn =~ /^([^\.]+)\.(.*)$/; |
406c51ee |
43 | } |
b3f6f6a6 |
44 | return $host; |
45 | } |
46 | elsif ($^O eq 'MacOS') { |
47 | chomp($host = `hostname`); |
48 | } |
49 | elsif ($^O eq 'VMS') { ## multiple varieties of net s/w makes this hard |
50 | $host = $ENV{'UCX$INET_HOST'} if defined($ENV{'UCX$INET_HOST'}); |
51 | $host = $ENV{'MULTINET_HOST_NAME'} if defined($ENV{'MULTINET_HOST_NAME'}); |
52 | if (index($host, '.') > 0) { |
53 | $fqdn = $host; |
54 | ($host, $domain) = $fqdn =~ /^([^\.]+)\.(.*)$/; |
406c51ee |
55 | } |
b3f6f6a6 |
56 | return $host; |
57 | } |
58 | else { |
59 | local $SIG{'__DIE__'}; |
686337f3 |
60 | |
b3f6f6a6 |
61 | # syscall is preferred since it avoids tainting problems |
62 | eval { |
63 | my $tmp = "\0" x 256; ## preload scalar |
64 | eval { |
65 | package main; |
66 | require "syscall.ph"; |
67 | defined(&main::SYS_gethostname); |
68 | } |
69 | || eval { |
70 | package main; |
71 | require "sys/syscall.ph"; |
72 | defined(&main::SYS_gethostname); |
73 | } |
74 | and $host = |
75 | (syscall(&main::SYS_gethostname, $tmp, 256) == 0) |
76 | ? $tmp |
77 | : undef; |
78 | } |
79 | |
80 | # POSIX |
81 | || eval { |
82 | require POSIX; |
83 | $host = (POSIX::uname())[1]; |
84 | } |
85 | |
86 | # trusty old hostname command |
87 | || eval { |
88 | chop($host = `(hostname) 2>/dev/null`); # BSD'ish |
89 | } |
90 | |
91 | # sysV/POSIX uname command (may truncate) |
92 | || eval { |
93 | chop($host = `uname -n 2>/dev/null`); ## SYSV'ish && POSIX'ish |
94 | } |
95 | |
96 | # Apollo pre-SR10 |
97 | || eval { $host = (split(/[:\. ]/, `/com/host`, 6))[0]; } |
98 | |
99 | || eval { $host = ""; }; |
100 | } |
101 | |
102 | # remove garbage |
103 | $host =~ s/[\0\r\n]+//go; |
104 | $host =~ s/(\A\.+|\.+\Z)//go; |
105 | $host =~ s/\.\.+/\./go; |
106 | |
107 | $host; |
406c51ee |
108 | } |
109 | |
b3f6f6a6 |
110 | |
406c51ee |
111 | sub _hostdomain { |
112 | |
b3f6f6a6 |
113 | # we already know it |
114 | return $domain |
115 | if (defined $domain); |
406c51ee |
116 | |
b3f6f6a6 |
117 | local $SIG{'__DIE__'}; |
118 | |
119 | return $domain = $NetConfig{'inet_domain'} |
120 | if defined $NetConfig{'inet_domain'}; |
121 | |
122 | # try looking in /etc/resolv.conf |
123 | # putting this here and assuming that it is correct, eliminates |
124 | # calls to gethostbyname, and therefore DNS lookups. This helps |
125 | # those on dialup systems. |
126 | |
127 | local *RES; |
128 | local ($_); |
406c51ee |
129 | |
b3f6f6a6 |
130 | if (open(RES, "/etc/resolv.conf")) { |
131 | while (<RES>) { |
132 | $domain = $1 |
133 | if (/\A\s*(?:domain|search)\s+(\S+)/); |
134 | } |
135 | close(RES); |
136 | |
137 | return $domain |
138 | if (defined $domain); |
139 | } |
406c51ee |
140 | |
b3f6f6a6 |
141 | # just try hostname and system calls |
406c51ee |
142 | |
b3f6f6a6 |
143 | my $host = _hostname(); |
144 | my (@hosts); |
406c51ee |
145 | |
b3f6f6a6 |
146 | @hosts = ($host, "localhost"); |
406c51ee |
147 | |
b3f6f6a6 |
148 | unless (defined($host) && $host =~ /\./) { |
149 | my $dom = undef; |
150 | eval { |
151 | my $tmp = "\0" x 256; ## preload scalar |
152 | eval { |
153 | package main; |
154 | require "syscall.ph"; |
155 | } |
156 | || eval { |
157 | package main; |
158 | require "sys/syscall.ph"; |
159 | } |
160 | and $dom = |
161 | (syscall(&main::SYS_getdomainname, $tmp, 256) == 0) |
162 | ? $tmp |
163 | : undef; |
164 | }; |
165 | |
166 | if ($^O eq 'VMS') { |
167 | $dom ||= $ENV{'TCPIP$INET_DOMAIN'} |
168 | || $ENV{'UCX$INET_DOMAIN'}; |
406c51ee |
169 | } |
170 | |
b3f6f6a6 |
171 | chop($dom = `domainname 2>/dev/null`) |
172 | unless (defined $dom || $^O =~ /^(?:cygwin|MSWin32)/); |
173 | |
174 | if (defined $dom) { |
175 | my @h = (); |
176 | $dom =~ s/^\.+//; |
177 | while (length($dom)) { |
178 | push(@h, "$host.$dom"); |
179 | $dom =~ s/^[^.]+.+// or last; |
180 | } |
181 | unshift(@hosts, @h); |
406c51ee |
182 | } |
b3f6f6a6 |
183 | } |
406c51ee |
184 | |
b3f6f6a6 |
185 | # Attempt to locate FQDN |
406c51ee |
186 | |
b3f6f6a6 |
187 | foreach (grep { defined $_ } @hosts) { |
188 | my @info = gethostbyname($_); |
406c51ee |
189 | |
b3f6f6a6 |
190 | next unless @info; |
406c51ee |
191 | |
b3f6f6a6 |
192 | # look at real name & aliases |
193 | my $site; |
194 | foreach $site ($info[0], split(/ /, $info[1])) { |
195 | if (rindex($site, ".") > 0) { |
406c51ee |
196 | |
b3f6f6a6 |
197 | # Extract domain from FQDN |
406c51ee |
198 | |
b3f6f6a6 |
199 | ($domain = $site) =~ s/\A[^\.]+\.//; |
200 | return $domain; |
201 | } |
406c51ee |
202 | } |
b3f6f6a6 |
203 | } |
406c51ee |
204 | |
b3f6f6a6 |
205 | # Look for environment variable |
406c51ee |
206 | |
b3f6f6a6 |
207 | $domain ||= $ENV{LOCALDOMAIN} || $ENV{DOMAIN}; |
406c51ee |
208 | |
b3f6f6a6 |
209 | if (defined $domain) { |
210 | $domain =~ s/[\r\n\0]+//g; |
211 | $domain =~ s/(\A\.+|\.+\Z)//g; |
212 | $domain =~ s/\.\.+/\./g; |
213 | } |
406c51ee |
214 | |
b3f6f6a6 |
215 | $domain; |
406c51ee |
216 | } |
217 | |
b3f6f6a6 |
218 | |
406c51ee |
219 | sub domainname { |
220 | |
b3f6f6a6 |
221 | return $fqdn |
222 | if (defined $fqdn); |
406c51ee |
223 | |
b3f6f6a6 |
224 | _hostname(); |
225 | _hostdomain(); |
406c51ee |
226 | |
b3f6f6a6 |
227 | # Assumption: If the host name does not contain a period |
228 | # and the domain name does, then assume that they are correct |
229 | # this helps to eliminate calls to gethostbyname, and therefore |
230 | # eleminate DNS lookups |
406c51ee |
231 | |
b3f6f6a6 |
232 | return $fqdn = $host . "." . $domain |
233 | if (defined $host |
234 | and defined $domain |
235 | and $host !~ /\./ |
236 | and $domain =~ /\./); |
406c51ee |
237 | |
b3f6f6a6 |
238 | # For hosts that have no name, just an IP address |
239 | return $fqdn = $host if defined $host and $host =~ /^\d+(\.\d+){3}$/; |
406c51ee |
240 | |
b3f6f6a6 |
241 | my @host = defined $host ? split(/\./, $host) : ('localhost'); |
242 | my @domain = defined $domain ? split(/\./, $domain) : (); |
243 | my @fqdn = (); |
406c51ee |
244 | |
b3f6f6a6 |
245 | # Determine from @host & @domain the FQDN |
406c51ee |
246 | |
b3f6f6a6 |
247 | my @d = @domain; |
686337f3 |
248 | |
406c51ee |
249 | LOOP: |
b3f6f6a6 |
250 | while (1) { |
251 | my @h = @host; |
252 | while (@h) { |
253 | my $tmp = join(".", @h, @d); |
254 | if ((gethostbyname($tmp))[0]) { |
255 | @fqdn = (@h, @d); |
256 | $fqdn = $tmp; |
257 | last LOOP; |
258 | } |
259 | pop @h; |
406c51ee |
260 | } |
b3f6f6a6 |
261 | last unless shift @d; |
262 | } |
406c51ee |
263 | |
b3f6f6a6 |
264 | if (@fqdn) { |
265 | $host = shift @fqdn; |
266 | until ((gethostbyname($host))[0]) { |
267 | $host .= "." . shift @fqdn; |
406c51ee |
268 | } |
b3f6f6a6 |
269 | $domain = join(".", @fqdn); |
270 | } |
271 | else { |
272 | undef $host; |
273 | undef $domain; |
274 | undef $fqdn; |
275 | } |
276 | |
277 | $fqdn; |
406c51ee |
278 | } |
279 | |
b3f6f6a6 |
280 | |
406c51ee |
281 | sub hostfqdn { domainname() } |
282 | |
b3f6f6a6 |
283 | |
406c51ee |
284 | sub hostname { |
b3f6f6a6 |
285 | domainname() |
286 | unless (defined $host); |
287 | return $host; |
406c51ee |
288 | } |
289 | |
b3f6f6a6 |
290 | |
406c51ee |
291 | sub hostdomain { |
b3f6f6a6 |
292 | domainname() |
293 | unless (defined $domain); |
294 | return $domain; |
406c51ee |
295 | } |
296 | |
b3f6f6a6 |
297 | 1; # Keep require happy |
406c51ee |
298 | |
299 | __END__ |
300 | |
301 | =head1 NAME |
302 | |
303 | Net::Domain - Attempt to evaluate the current host's internet name and domain |
304 | |
305 | =head1 SYNOPSIS |
306 | |
c20cde70 |
307 | use Net::Domain qw(hostname hostfqdn hostdomain domainname); |
406c51ee |
308 | |
309 | =head1 DESCRIPTION |
310 | |
311 | Using various methods B<attempt> to find the Fully Qualified Domain Name (FQDN) |
312 | of the current host. From this determine the host-name and the host-domain. |
313 | |
314 | Each of the functions will return I<undef> if the FQDN cannot be determined. |
315 | |
316 | =over 4 |
317 | |
318 | =item hostfqdn () |
319 | |
320 | Identify and return the FQDN of the current host. |
321 | |
c20cde70 |
322 | =item domainname () |
323 | |
324 | An alias for hostfqdn (). |
325 | |
406c51ee |
326 | =item hostname () |
327 | |
328 | Returns the smallest part of the FQDN which can be used to identify the host. |
329 | |
330 | =item hostdomain () |
331 | |
332 | Returns the remainder of the FQDN after the I<hostname> has been removed. |
333 | |
334 | =back |
335 | |
336 | =head1 AUTHOR |
337 | |
338 | Graham Barr <gbarr@pobox.com>. |
339 | Adapted from Sys::Hostname by David Sundstrom <sunds@asictest.sc.ti.com> |
340 | |
341 | =head1 COPYRIGHT |
342 | |
343 | Copyright (c) 1995-1998 Graham Barr. All rights reserved. |
344 | This program is free software; you can redistribute it and/or modify |
345 | it under the same terms as Perl itself. |
346 | |
347 | =cut |