phase1/findbin.pl

   1 #!/usr/bin/env perl
   2
   3 use strict;
   4 use warnings;
   5
   6 sub vernum($) {
   7         if ($_[0] =~  m!^((?:\d+\.)+\d+)$!) {
   8                 my ($maj, $min) = split /\./, $1;
   9                 return int($maj) * 256 + int($min);
  10         }
  11
  12         return 0;
  13 }
  14
  15 sub vercmp($$$) {
  16         my ($op, $v1, $v2) = @_;
  17
  18         if    ($op eq 'lt') { return $v1  < $v2 }
  19         elsif ($op eq 'le') { return $v1 <= $v2 }
  20         elsif ($op eq 'gt') { return $v1  > $v2 }
  21         elsif ($op eq 'ge') { return $v1 >= $v2 }
  22         elsif ($op eq 'eq') { return $v1 == $v2 }
  23
  24         return 0;
  25 }
  26
  27 sub findbin($$$) {
  28         my ($basename, $compare, $maxvstr) = @_;
  29
  30         my $lastversion = 0;
  31         my $cmpversion = vernum($maxvstr);
  32         my $prog = undef;
  33
  34         foreach my $dir (split /:/, $ENV{'PATH'}) {
  35                 foreach my $bin (glob("$dir/$basename?*"), "$dir/$basename") {
  36                         if (-x $bin && open BIN, '-|', $bin, '--version') {
  37                                 my $vers = 0;
  38                                 my $line = readline(BIN) || '';
  39
  40                                 foreach my $token (split /\s+/, $line) {
  41                                         $vers = vernum($token);
  42                                         last if $vers > 0;
  43                                 }
  44
  45                                 if ($vers > 0 && (!$cmpversion || vercmp($compare, $vers, $cmpversion))) {
  46                                         if ($vers > $lastversion) {
  47                                                 $lastversion = $vers;
  48                                                 $prog = $bin;
  49                                         }
  50                                 }
  51
  52                                 close BIN;
  53                         }
  54                 }
  55         }
  56
  57         return $prog;
  58 }
  59
  60 my $bin = findbin($ARGV[0], $ARGV[1], $ARGV[2]);
  61
  62 if (defined $bin) {
  63         printf "%s\n", $bin;
  64         exit 0;
  65 }
  66 else {
  67         warn "Cannot find a $ARGV[0] command with version $ARGV[1] $ARGV[2]\n";
  68         exit 1;
  69 }