Hi!
I wrote something which does this for some internal applikation which
uses FAI_CLASSES to decide which things to do.
The tool read /etc/fai/FAI_CLASSES and checks where the expr specified
as cmdline parameter matches for these classes.
See the perl script attached.
Ciao
Max
--
Follow the white penguin.
#!/usr/bin/perl -w
#
# Copyright 2007 Maximilian Wihelm <[EMAIL PROTECTED]>
#
use strict;
if (! @ARGV) {
die "Usage: $0 class_expr\n";
}
my $expr = $ARGV[0];
# The set of control chars we know of
my $control_chars = '[[:space:]()!&|]';
my $control_chars_without_exclamation_mark = '[()&|]';
my $FAI_CLASSES = "/etc/fai/FAI_CLASSES";
my $debug = 0;
#
# Keep your fingers of of this...
# Hashref to store class names
my $class = {};
# Scalar to store the logical expression
my $check_expr = "";
#
# Read CLASSES of this host and initialize them as '1' (set)
open (LIST, "<", $FAI_CLASSES)
or die "Could not open list file\n";
while (my $class_name = <LIST>) {
# Strip CR/LF
chomp $class_name;
print STDERR "Setting \$class->{$class_name} = 1\n" if ($debug);
$class->{$class_name} = 1;
}
close (LIST);
#
# Compatibility glue
if (! grep { /$control_chars_without_exclamation_mark/ } $expr) {
$expr =~ s/[[:space:]]+/ & /g;
}
#
# Read CALSSES used in expression and initialize them as '0' (unset) IFF
# not initialized before!
foreach my $word (split /$control_chars/, $expr) {
next if ($word eq "");
if (! $class->{$word}) {
print STDERR "Setting \$$word = 0\n" if ($debug);
$class->{$word} = 0;
}
}
#
# Build up a logical expression which can be eval'uated
my $word_start = 1;
my $reading_word = 0;
foreach my $char (split ('', $expr)) {
if ($char =~ m/$control_chars/) {
if ($reading_word) {
$check_expr .= "}";
$reading_word = 0;
}
$check_expr .= $char;
$word_start = 1;
} else {
if ($word_start) {
$check_expr .= "\$class->{$char";
$word_start = 0;
$reading_word = 1;
} else {
$check_expr .= $char;
}
}
}
if ($reading_word) {
$check_expr .= "}";
}
print STDERR "check_expr = \"$check_expr\"\n" if($debug);
#
# Evaluate expression and decide fate.
if (eval $check_expr) {
# print "Jo man\n";
exit 0;
} else {
# print "Noe.\n";
exit 1;
}
