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1 | package Sys::Hostname; |
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2 | |
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3 | use Carp; |
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4 | require Exporter; |
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5 | @ISA = qw(Exporter); |
6 | @EXPORT = qw(hostname); |
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7 | |
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8 | =head1 NAME |
9 | |
10 | Sys::Hostname - Try every conceivable way to get hostname |
11 | |
12 | =head1 SYNOPSIS |
13 | |
14 | use Sys::Hostname; |
15 | $host = hostname; |
16 | |
17 | =head1 DESCRIPTION |
18 | |
19 | Attempts several methods of getting the system hostname and |
20 | then caches the result. It tries C<syscall(SYS_gethostname)>, |
21 | C<`hostname`>, C<`uname -n`>, and the file F</com/host>. |
22 | If all that fails it C<croak>s. |
23 | |
24 | All nulls, returns, and newlines are removed from the result. |
25 | |
26 | =head1 AUTHOR |
27 | |
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28 | David Sundstrom E<lt>F<sunds@asictest.sc.ti.com>E<gt> |
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29 | |
30 | Texas Instruments |
31 | |
32 | =cut |
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33 | |
34 | sub hostname { |
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35 | |
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36 | # method 1 - we already know it |
37 | return $host if defined $host; |
38 | |
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39 | if ($^O eq 'VMS') { |
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40 | |
41 | # method 2 - no sockets ==> return DECnet node name |
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42 | eval { local $SIG{__DIE__}; $host = (gethostbyname('me'))[0] }; |
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43 | if ($@) { return $host = $ENV{'SYS$NODE'}; } |
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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! |
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59 | $host = ''; |
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60 | Carp::croak "Cannot get host name of local machine"; |
61 | |
62 | } |
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63 | elsif ($^O eq 'MSWin32') { |
64 | ($host) = gethostbyname('localhost'); |
65 | chomp($host = `hostname 2> NUL`) unless defined $host; |
66 | return $host; |
67 | } |
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68 | elsif ($^O eq 'epoc') { |
69 | $host = 'localhost'; |
70 | return $host; |
71 | } |
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72 | else { # Unix |
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73 | |
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74 | # method 2 - syscall is preferred since it avoids tainting problems |
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75 | eval { |
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76 | local $SIG{__DIE__}; |
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77 | require "syscall.ph"; |
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78 | $host = "\0" x 65; ## preload scalar |
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79 | syscall(&SYS_gethostname, $host, 65) == 0; |
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80 | } |
81 | |
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82 | # method 2a - syscall using systeminfo instead of gethostname |
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83 | # -- needed on systems like Solaris |
84 | || eval { |
85 | local $SIG{__DIE__}; |
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86 | require "sys/syscall.ph"; |
87 | require "sys/systeminfo.ph"; |
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88 | $host = "\0" x 65; ## preload scalar |
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89 | syscall(&SYS_systeminfo, &SI_HOSTNAME, $host, 65) != -1; |
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90 | } |
91 | |
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92 | # method 3 - trusty old hostname command |
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93 | || eval { |
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94 | local $SIG{__DIE__}; |
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95 | local $SIG{CHLD}; |
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96 | $host = `(hostname) 2>/dev/null`; # bsdish |
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97 | } |
98 | |
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99 | # method 4 - use POSIX::uname(), which strictly can't be expected to be |
100 | # correct |
101 | || eval { |
102 | local $SIG{__DIE__}; |
103 | require POSIX; |
104 | $host = (POSIX::uname())[1]; |
105 | } |
106 | |
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107 | # method 5 - sysV uname command (may truncate) |
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108 | || eval { |
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109 | local $SIG{__DIE__}; |
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110 | $host = `uname -n 2>/dev/null`; ## sysVish |
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111 | } |
112 | |
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113 | # method 6 - Apollo pre-SR10 |
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114 | || eval { |
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115 | local $SIG{__DIE__}; |
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116 | ($host,$a,$b,$c,$d)=split(/[:\. ]/,`/com/host`,6); |
117 | } |
118 | |
119 | # bummer |
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120 | || Carp::croak "Cannot get host name of local machine"; |
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121 | |
122 | # remove garbage |
123 | $host =~ tr/\0\r\n//d; |
124 | $host; |
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125 | } |
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126 | } |
127 | |
128 | 1; |