hostuuid

   1 #!/usr/bin/perl
   2
   3 #This program is free software: you can redistribute it and/or modify
   4 #it under the terms of the GNU General Public License as published by
   5 #the Free Software Foundation, either version 3 of the License, or
   6 #(at your option) any later version.
   7 #
   8 #This program is distributed in the hope that it will be useful,
   9 #but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 #MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 #GNU General Public License for more details.
  12 #
  13 #You should have received a copy of the GNU General Public License
  14 #along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15
  16 # Written by Richard Hartmann in 2009, feel free to email
  17 # richih dot mailinglist -at- gmail dot com with questions.
  18
  19 =head1 NAME
  20
  21 hostuuid - program to create, display, check /etc/hostuuid
  22
  23 =cut
  24
  25 use strict;
  26 use warnings;
  27
  28 use UUID::Tiny;
  29 use Getopt::Long qw(:config no_ignore_case bundling);
  30 use File::Basename;
  31
  32 my $VERSION;
  33 $VERSION = '1.2';
  34 my $program = basename($0);
  35
  36 my $file = '/etc/hostuuid';
  37 my $force;
  38 my $print_version;
  39 my $print_help;
  40 my $input;
  41 my $create_uuid = 0;
  42 my $quiet;
  43 my $no_stdin=0;
  44
  45 =head1 SYNOPSIS
  46
  47 B<hostuuid> [-f I<file>]
  48
  49 B<hostuuid> -c [--force] [-f I<file>]
  50
  51 echo 4f1cc27c-6c7b-4419-9db6-5b2f6a600b37 | B<hostuuid>
  52
  53 =head1 DESCRIPTION
  54
  55 B<hostuuid> creates, displays and verifies the contents of /etc/hostuuid or any other file.
  56 It will also read anything on STDIN and verify if it's a UUID.
  57
  58 =head1 OPTIONS
  59
  60 =over 4
  61
  62 =item B<-f|--file> I<filename>
  63
  64 The I<filename> B<hostuuid> will read from/write to.
  65
  66 =item B<--force>
  67
  68 Force creation of new UUID.
  69
  70 =item B<-c|--create>
  71
  72 Create a new UUID.
  73
  74 =item B<-q|--quiet>
  75
  76 Don't print anything.
  77 B<hostuuid> will still exit with proper return codes for you to script with.
  78
  79 =item B<--input>
  80
  81 Save this UUID to I<filename>.
  82 Defaults to /etc/hostuuid
  83
  84 =item B<--nostdin>
  85
  86 Do not listen on STDIN.
  87 Needed to work around a bug in debconf.
  88
  89 =item B<-h|-?|--help>
  90
  91 Print help.
  92
  93 =item B<--version>
  94
  95 Print version information.
  96
  97 =back
  98
  99 =head1 FILES
 100
 101 /etc/hostuuid
 102
 103 =head1 REQUIRES
 104
 105 Perl 5.8, UUID::Tiny
 106
 107 =head1 SEE ALSO
 108
 109 perl(1)
 110
 111 =head1 AUTHOR
 112
 113 Richard Hartmann <richih.mailinglist@gmail.com>
 114
 115 =cut
 116
 117 GetOptions (
 118             'file|f=s'  => \$file,
 119             'force'     => \$force,
 120             'create|c'  => \$create_uuid,
 121             'input=s'   => \$input,
 122             'quiet|q'   => \$quiet,
 123             'nostdin'   => \$no_stdin,
 124             'help|h|?'  => \$print_help,
 125             'version'   => \$print_version,
 126            ) or print_help(255);
 127
 128 sub print_version() {
 129         unless ($quiet) {
 130                 print <<VERSION;
 131 $program: version $VERSION
 132
 133 This program is released under GPLv3
 134 Written by Richard Hartmann for Debian and Grml
 135 VERSION
 136         }
 137         exit 0;
 138 }
 139
 140 sub print_help {
 141         my ($exit_code) = @_;
 142         unless ($quiet) {
 143                 print <<HELP;
 144 Help for $program:
 145
 146   -f, --file     : file to read from/write to. Defaults to /etc/hostuuid
 147   --force        : force creation of new UUID
 148   -c, --create   : create & save UUID
 149   -q, --quiet    : Don't print anything
 150   --input        : Save UUID to file. Defaults to /etc/hostuuid
 151   --nostdin      : Do not listen on STDIN
 152   -h, -?, --help : print this help
 153   --version      : print version
 154 HELP
 155         }
 156         exit $exit_code;
 157 }
 158
 159 sub create_uuid() {
 160         my $uuid = find_hostuuid();
 161         if ($uuid && !$force) {
 162                 print STDERR "$program: Found UUID '$uuid' in '$file'. Aborting!\n" unless $quiet;
 163                 exit 101;
 164         } else {
 165                 save_uuid(create_UUID_as_string(UUID_V4));
 166         }
 167 }
 168
 169 sub find_hostuuid() {
 170         return 0 unless ((-e $file && $create_uuid) || !$create_uuid);
 171         open (F, "<", "$file") or do {
 172                 die "$program: Could not open file: '$file'\: $!\n" unless $quiet;
 173                 exit 2;
 174         };
 175         my $uuid = check_uuid(<F>);
 176         close (F);
 177         return $uuid;
 178 }
 179
 180 sub check_uuid {
 181         my ($string) = @_;
 182         return $1 if ($string =~ /^([0-9a-f]{8}-([0-9a-f]{4}-){3}[0-9a-f]{12})$/i);
 183         return undef;
 184 }
 185
 186 sub save_uuid {
 187         my ($uuid) = @_;
 188         unless (check_uuid($uuid)) {
 189                 print "$uuid is NOT a valid UUID\n" unless $quiet;
 190                 exit 3;
 191         }
 192         open (F, ">", "$file") or do {
 193                 die "$program: Could not open file: '$file'\: $!\n" unless $quiet;
 194                 exit 5;
 195         };
 196         print "$program\: Stored UUID '$uuid' in '$file'\n" unless $quiet;
 197         print F "$uuid\n";
 198         close (F);
 199         exit 0;
 200 }
 201
 202 sub main() {
 203         unless ($no_stdin || -t STDIN) { ## we need to test for $no_stdin cause debconf makes us hang, otherwise
 204                 my $uuid = check_uuid(<STDIN>);
 205                 if ($uuid) {
 206                         print "$uuid is a valid UUID\n" unless $quiet;
 207                         exit 0;
 208                 } else {
 209                         print "NOT a valid UUID\n" unless $quiet;
 210                         exit 105;
 211                 }
 212         }
 213         print_version()   if $print_version;
 214         print_help(0)     if $print_help;
 215         save_uuid($input) if $input;
 216         create_uuid()     if $create_uuid;
 217
 218         my $uuid = find_hostuuid();
 219         if ($uuid) {
 220                 print "$uuid\n" unless $quiet;
 221                 exit 0;
 222         } else {
 223                 print STDERR "$program: Could not find valid UUID in '$file'\n" unless $quiet;
 224                 exit 100;
 225         }
 226 }
 227
 228 main();