munin-node.in

#!@@PERL@@ -wT
#
# Copyright (C) 2004 Audun Ytterdal, Jimmy Olsen
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; version 2 dated June,
# 1991.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
#
#
# $Id$
#
# $Log$
# Revision 1.19  2004/12/09 20:03:25  jimmyo
# Added two new plugins contributed by Jacques Caruso, generic/exim_mailqueue_alt and generic/mailscanner.
#
# Revision 1.18  2004/12/09 19:34:54  jimmyo
# host_name in plugin-conf.d now overrides plugin output.
#
# Revision 1.17  2004/11/20 23:17:47  jimmyo
# Added per-plugin timeouts, contributed by Chan Wilson (SF#881044).
#
# Revision 1.16  2004/11/16 20:00:42  jimmyo
# License cleanups.
#
# Revision 1.15  2004/11/10 15:34:18  jimmyo
# Added new plugin generic/apc_nis to monitor APC UPS, contributed by xavier.
#
# Revision 1.14  2004/05/12 20:33:28  jimmyo
# Made the allow/deny syntax more flexible.
#
# Revision 1.13  2004/05/10 21:16:11  jimmyo
# Allow/deny in munin-node can now be configured per plugin, in addition to "globally" for the whole node.
#
# Revision 1.12  2004/04/27 21:18:33  jimmyo
# Fixed a problem in the node when running as a non-root user and using sudo to run the plugins (Deb#236694).
#
# Revision 1.11  2004/02/05 18:05:59  jimmyo
# Improved timeout-handling in node (Deb#224480).
#
# Revision 1.10  2004/02/05 17:35:41  jimmyo
# Made client timeouts configurable (not per plugin).
#
# Revision 1.9  2004/02/01 21:34:59  jimmyo
# Remove dependency on pgrep (use process groups instead). (SF#881049)
#
# Revision 1.8  2004/02/01 20:46:29  jimmyo
# Added better logging of plugin failures in the node. (SF#881045)
#
# Revision 1.7  2004/01/29 19:39:00  jimmyo
# Generic plugins now use printf instead of echo -n, as this is more portable (SF#885564)
#
# Revision 1.6  2004/01/29 18:07:52  jimmyo
# Bugfix from bug introduced 30 minutes ago
#
# Revision 1.5  2004/01/29 17:36:19  jimmyo
# Updated copyright information
#
# Revision 1.4  2004/01/29 16:56:54  jimmyo
# Fixed "group" bug. Added support for multiple and optional groups
#
# Revision 1.3  2004/01/17 22:04:29  toreanderson
# Change the name in process listing to contain only the path to the munin-node
# executable, without '/usr/bin/perl -wT' prepending it.
#
# Revision 1.2  2004/01/15 15:20:01  jimmyo
# Making things workable after name change. Upping for test verwion.
#
# Revision 1.1  2004/01/02 18:50:00  jimmyo
# Renamed occurrances of lrrd -> munin
#
# Revision 1.1.1.1  2004/01/02 15:18:06  jimmyo
# Import of LRRD CVS tree after renaming to Munin
#
# Revision 1.28  2003/12/18 18:51:37  jimmyo
# added configuration option "ignore_file", which takes regex for files to ignore (e.g. rpmnew/save) (Deb#224265).
#
# Revision 1.27  2003/12/18 17:58:18  jimmyo
# Do a fake clean of the environment because of the taint checking.
#
# Revision 1.26  2003/12/17 21:29:26  jimmyo
# Don\'t try to change uid/gid if not running as root. (Deb#224300)
#
# Revision 1.25  2003/12/10 15:30:02  jimmyo
# Set path before trying to get hostname
#
# Revision 1.24  2003/12/10 15:11:40  jimmyo
# A couple of bugfixes.
#
# Revision 1.23  2003/11/17 09:23:08  jimmyo
# Fix taint checking for getting hostname
#
# Revision 1.22  2003/11/17 09:20:09  jimmyo
# Fix for machines which don't have "host".
#
# Revision 1.21  2003/11/07 17:43:16  jimmyo
# Cleanups and log entries
#
#

package MyPackage;

use strict;
use vars qw(@ISA);
use Getopt::Long;
use Net::Server::Fork; # any personality will do

chdir ("/");

# "Clean" environment to disable taint-checking on the environment. We _know_
# that the environment is insecure, but we want to let admins shoot themselves
# in the foot with it, if they want to.
foreach my $key (keys %ENV)
{
        $ENV{$key} =~ /^(.*)$/;
        $ENV{$key} = $1;
}

$0 =~ /^(.*)$/; # for some strange reason won't "$0 = $0;" work.
$0 = $1;

@ISA = qw(Net::Server::Fork);
my @ORIG_ARGV = @ARGV;
my %services;
my %nodes;
my $servicedir="@@CONFDIR@@/plugins";
my $sconfdir="@@CONFDIR@@/plugin-conf.d";
my $conffile="@@CONFDIR@@/munin-node.conf";
my $FQDN="";
my $do_usage = 0;
my $DEBUG = 0;
my $do_version = 0;
my $VERSION="@@VERSION@@";
my $defuser = getpwnam ("nobody");
my $defgroup= getgrnam ("munin");
my $paranoia= 0;
my @ignores = ();
my %sconf   = ('timeout' => 10);
my $caddr   = "";

$do_usage=1  unless 
GetOptions ( "config=s"     => \$conffile,
             "debug!"       => \$DEBUG,
             "version!"     => \$do_version,
             "paranoia!"    => \$paranoia,
             "help"         => \$do_usage );

if ($do_usage)
{
    print "Usage: $0 [options]

Options:
    --help              View this message.
    --config <file>     Use <file> as configuration file. 
                        [/etc/munin/munin-node.conf]
    --[no]paranoia      Only run plugins owned by root. Check permissions.
                        [--noparanoia]
    --debug             View debug messages.
    --version           View version information.

";
    exit 0;
}

if ($do_version)
{
	print "munin-node (munin-node) version $VERSION.
Written by Audun Ytterdal, Jimmy Olsen, Tore Anderson / Linpro AS

Copyright (C) 2002-2004
This is free software released under the GNU Public License. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
";
	exit 0;
}

# Reset ARGV (for HUPing)
@ARGV = @ORIG_ARGV;

# Check permissions of configuration

if (!&check_perms ($servicedir) or !&check_perms ($conffile))
{
	die "Fatal error. Bailing out.";
}

if (! -f $conffile) {
  print "ERROR: Cannot open $conffile\n";
  exit 1;
}

# A hack to overide the hostname if everyhing thing else fails
open FILE,$conffile or die "Cannot open $conffile\n";
while (<FILE>) {
  chomp;
  s/#.*//;                # no comments
  s/^\s+//;               # no leading white
  s/\s+$//;               # no trailing white
  next unless length;     # anything left?
  /(^\w*)\s+(.*)/;
  if (($1 eq "host_name" or $1 eq "hostname") and $2)
  {
      $FQDN=$2;
  }
  elsif (($1 eq "default_plugin_user" or $1 eq "default_client_user") and $2)
  {
      my $tmpid = $2;
      my $defuser = &get_uid ($tmpid);
      if (! defined ($defuser))
      {
	  die "Default user defined in \"$conffile\" does not exist ($tmpid)";
      }
  }
  elsif (($1 eq "default_plugin_group" or $1 eq "default_client_group") and $2)
  {
      my $tmpid = $2;
      $defgroup = &get_gid ($tmpid);
      if (! defined ($defgroup))
      {
	  die "Default group defined in \"$conffile\" does not exist ($tmpid)";
      }
  }
  elsif (($1 eq "paranoia") and defined $2)
  {
	  if ("$2" eq "no" or "$2" eq "false" or "$2" eq "off" or "$2" eq "0")
	  {
		  $paranoia = 0;
	  }
	  else
	  {
		  $paranoia = 1;
	  }
  }
  elsif (($1 eq "ignore_file") and defined $2)
  {
      push @ignores, $2;
  }
  elsif (($1 eq "timeout") and defined $2)
  {
      $sconf{'timeout'} = $2;
  }
}

$FQDN ||= &get_fq_hostname;

$ENV{FQDN}=$FQDN;

MyPackage->run(conf_file => $conffile,
	       pid_file => "@@STATEDIR@@/munin-node.pid");
exit;




### over-ridden subs below

sub pre_loop_hook {
    my $self = shift;
	print STDERR "In pre_loop_hook.\n" if $DEBUG;
    &load_services;
    $self->SUPER::pre_loop_hook;
}

sub show_version {
  print "munins node on $FQDN version: $VERSION\n"
}

sub show_nodes {
  for my $node (keys %nodes) {
    print "$node\n";
  }
  print ".\n";
}

sub get_fq_hostname {
    my $hostname;
    eval {
        require Net::Domain;
        $hostname = Net::Domain::hostfqdn();
    };
    return $hostname if $hostname;

    $hostname = `hostname`;  # Fall$
    chomp($hostname);
    $hostname =~ s/\s//g;
    return $hostname;
}

sub load_services {
    if (opendir (DIR,$sconfdir))
    {
FILES:
	for my $file (grep { -f "$sconfdir/$_" } readdir (DIR))
	{
	    next if $file =~ m/^\./; # Hidden files
	    next if $file !~ m/^([-\w.]+)$/; # Skip if any weird chars
	    $file = $1; # Not tainted anymore.
	    foreach my $regex (@ignores)
	    {
		next FILES if $file =~ /$regex/;
	    }
	    if (!&load_auth_file ($sconfdir, $file, \%sconf))
	    {
		warn "Something wicked happened while reading \"$servicedir/$file\". Check the previous log lines for spesifics.";
	    }
	}
	closedir (DIR);
    }
    
    opendir (DIR,$servicedir) || die "Cannot open plugindir: $servicedir $!";
FILES:
    for my $file (grep { -f "$servicedir/$_" } readdir(DIR)) {
	next if $file =~ m/^\./; # Hidden files
	next if $file =~ m/.conf$/; # Config files
	next if $file !~ m/^([-\w.]+)$/; # Skip if any weird chars
	$file = $1; # Not tainted anymore.
	foreach my $regex (@ignores)
	{
	    next FILES if $file =~ /$regex/;
	}
	next if (! -x "$servicedir/$file"); # File not executeable
	print "file: '$file'\n" if $DEBUG;
	$services{$file}=1;
	my @rows = &run_service($file,"config", 1);
	my $node = &get_var (\%sconf, $file, 'host_name');

	for my $row (@rows) {
	  print "row: $row\n" if $DEBUG;
	  if ($row =~ m/^host_name (.+)$/) {
	    print "Found host_name, using it\n" if $DEBUG;
	    $node = $1;
	  }
	} 
	$node ||= $FQDN;
	$nodes{$node}{$file}=1;
    }
    closedir DIR;
}

sub print_service {
  my (@lines) = @_;
  for my $line (@lines) {
    print "$line\n";
  }
  print ".\n";
}

sub list_services {
    my $node = $_[0] || $FQDN;
    print join " ", grep { &has_access ($_); } keys %{$nodes{$node}};
    #print join " ", keys %{$nodes{$node}};
    print "\n";
}

sub has_access {
	my $serv   = shift;
	my $host   = $caddr;
	my $rights = &get_var_arr (\%sconf, $serv, 'allow_deny');

	unless (@{$rights})
	{
		return 1;
	}
	print STDERR "DEBUG: Checking access: $host;$serv;\n" if $DEBUG;
	foreach my $ruleset (@{$rights})
	{
		foreach my $rule (@{$ruleset})
		{
			print STDERR "DEBUG: Checking access: $host;$serv;", $rule->[0], $rule->[1], ";\n" if $DEBUG;
#			if ($rule->[1] =~ /\//)
#			{ # CIDR
#				print "DEBUG: CIDR $host;$serv;$rule->[1];\n";
#				return 1;
#			}
#			else
#			{ # regex
				if ($host =~ m($rule->[1]))
				{
					if ($rule->[0] eq "allow")
					{
						return 1;
					}
					else
					{
						return 0;
					}
				}
#			}
		}
	}
	return 1;
}

sub logger {
    my $text  = shift;
    my @date  = localtime (time);

    printf STDERR ("%d/%02d/%02d-%02d:%02d:%02d %s\n", $date[5]+1900, $date[4]+1, 
	    $date[3], $date[2], $date[1], $date[0], $text);
}

sub reap_children {
  my $child = shift;
  my $text = shift;
  return unless $child;
  if (kill (0, $child)) 
    { 
      print ("# timeout pid $child - killing..."); 
      logger ("Plugin timeout: $text (pid $child)");
      kill (-1, $child); sleep 2; 
      kill (-9, $child);
      print ("done\n");
    } 
}

sub run_service {
  my ($service,$command,$autoreap) = @_;
  $command ||="";
  my @lines = ();;
  my $timed_out = 0;
  if ($services{$service} and ($caddr eq "" or &has_access ($service))) {
    my $child = 0;
    my $timeout = get_var (\%sconf, $service, 'timeout');
    $timeout = $sconf{'timeout'} 
    	unless defined $timeout and $timeout =~ /^\d+$/;

    if ($child = open (CHILD, "-|")) {
      eval {
	  local $SIG{ALRM} = sub { $timed_out=1; die "$!\n"};
	  alarm($timeout);
	  while(<CHILD>) {
	    push @lines,$_;
	  }
      };
      if( $timed_out ) {
	  reap_children($child, "$service $command: $@");
	  close (CHILD);
          return ();
      }
      unless (close CHILD)
      {
	  if ($!)
	  {
	      # If Net::Server::Fork is currently taking care of reaping,
	      # we get false errors. Filter them out.
	      unless (defined $autoreap and $autoreap) 
	      {
		  logger ("Error while executing plugin \"$service\": $!");
	      }
	  }
	  else
	  {
	      logger ("Plugin \"$service\" exited with status $?. --@lines--");
	  }
      }
    }
    else {
      if ($child == 0) {
	# New process group...
	POSIX::setsid();
        # Setting environment
	$sconf{$service}{user}    = &get_var (\%sconf, $service, 'user');
	$sconf{$service}{group}   = &get_var (\%sconf, $service, 'group');
	$sconf{$service}{command} = &get_var (\%sconf, $service, 'command');
	&get_var (\%sconf, $service, 'env', \%{$sconf{$service}{env}});
	
	if ($< == 0) # If root...
	{
		# Giving up gid egid uid euid
		my $u  = (defined $sconf{$service}{'user'}?
			$sconf{$service}{'user'}:
			$defuser);
		my $g  = $defgroup;
		my $gs = "$g $g" .
			($sconf{$service}{'group'}?" $sconf{$service}{group}":"");

		print "# Want to run as euid/egid $u/$g\n" if $DEBUG;

		$( = $g    unless $g == 0;
		$) = $gs   unless $g == 0;
		$< = $u    unless $u == 0;
		$> = $u    unless $u == 0;

		if ($> != $u or $g != (split (' ', $)))[0])
		{
			print "# Can't drop privileges. Bailing out. (wanted uid=",
			    ($sconf{$service}{'user'} || $defuser), " gid=\"",
			    $gs, "\"($g), got uid=$> gid=\"$)\"(", 
			    (split (' ', $)))[0], ").\n";
			logger ("Plugin \"$service\" Can't drop privileges. ".
			    "Bailing out. (wanted uid=".
			    ($sconf{$service}{'user'} || $defuser). " gid=\"".
			    $gs. "\"($g), got uid=$> gid=\"$)\"(". 
			    (split (' ', $)))[0]. ").\n");
			exit 1;
		}
	}
	print "# Running as uid/gid/euid/egid $</$(/$>/$)\n" if $DEBUG;
	if (!&check_perms ("$servicedir/$service"))
	{
	    print "# Error: unsafe permissions. Bailing out.";
	    logger ("Error: unsafe permissions. Bailing out.");
	    exit 2;
	}

	# Setting environment...
	if (exists $sconf{$service}{'env'} and
			defined $sconf{$service}{'env'})
	{
	    foreach my $key (keys %{$sconf{$service}{'env'}})
	    {
		print "# Setting environment $key=$sconf{$service}{env}{$key}\n" if $DEBUG;
		$ENV{"$key"} = $sconf{$service}{'env'}{$key};
	    }
	}
	if (exists $sconf{$service}{'command'} and 
		defined $sconf{$service}{'command'})
	{
	    my @run = ();
	    foreach my $t (@{$sconf{$service}{'command'}})
	    {
		if ($t =~ /^%c$/)
		{
		    push (@run, "$servicedir/$service", $command);
		}
		else
		{
		    push (@run, $t);
		}
	    }
	    print STDERR "# About to run \"", join (' ', @run), "\"\n" if $DEBUG;
	    print "# About to run \"", join (' ', @run), "\"\n" if $DEBUG;
	    exec (@run) if @run;
	}
	else
	{
	    print "# Execing...\n" if $DEBUG;
	    exec ("$servicedir/$service", $command);
	}
      }
      else {
	print "# Unable to fork.\n";
	logger ("Unable to fork.");
      }
    }
    wait;
    alarm(0);
  }
  else {
    print "# Unknown service\n";
  }
  chomp @lines;
  return (@lines);
}

sub process_request {
  my $self = shift;
  $caddr = $self->{server}->{peeraddr};
  print "# munin node at $FQDN\n";
  local $SIG{ALRM} = sub { logger ("Connection timed out."); die "timeout" };
  alarm($sconf{'timeout'});
  while( <STDIN> ){
    alarm($sconf{'timeout'});
    chomp;
    if (m/^list\s*([0-9a-zA-Z\.\-]+)?/) {
      &list_services($1);
    }
    elsif (/^quit/ || /^\./) {
      exit 1;
    }
    elsif (/^version/) {
      &show_version;
	}
    elsif (/^nodes/) {
      &show_nodes;
    }
    elsif (/^fetch\s?(\S*)/) {
      print_service (&run_service($1)) 
    }
    elsif (/^config\s?(\S*)/) {
      print_service (&run_service($1,"config"));
    } else  {
      print "# Unknown command. Try list, nodes, config, fetch, version or quit\n";
    }
  }
}

sub get_uid
{
    my $user = shift;
    return undef if (!defined $user);

    if ($user !~ /\d/)
    {
	$user = getpwnam ($user);
    }
    return $user;
}

sub get_gid
{
    my $group = shift;
    return undef if (!defined $group);

    if ($group !~ /\d/)
    {
	$group = getgrnam ($group);
    }
    return $group;
}

sub load_auth_file 
{
    my ($dir, $file, $sconf) = @_;
    my $service = $file;

    if (!defined $dir or !defined $file or !defined $sconf)
    {
	return undef;
    }

    return undef if (!&check_perms ($dir));
    return undef if (!&check_perms ("$dir/$file"));

    if (!open (IN, "$dir/$file"))
    {
	warn "Could not open file \"$dir/$file\" for reading ($!), skipping plugin\n";
	return undef;
    }
    while (<IN>)
    {
	chomp;
	s/#.*$//;
	next unless /\S/;
	s/\s+$//g;
	print "DEBUG: Config: $service: $_\n" if $DEBUG;
	if (/^\s*\[([^\]]+)\]\s*$/)
	{
	    $service = $1;
	}
	elsif (/^\s*user\s+(\S+)\s*$/)
	{
	    my $tmpid = $1;
	    $sconf->{$service}{'user'} = &get_uid ($tmpid);
	    print "DEBUG: Config: $service->uid = ", $sconf->{$service}{'user'}, "\n" if $DEBUG;
	    if (!defined $sconf->{$service}{'user'})
	    {
		warn "User \"$tmpid\" in configuration file \"$dir/$file\" nonexistant. Skipping plugin.";
		return undef;
	    }
	}
	elsif (/^\s*group\s+(.+)\s*$/)
	{
	    my $tmpid = $1;
	    foreach my $group (split /\s*,\s*/, $tmpid)
	    {
		my $optional = 0;

		if ($group =~ /^\(([^)]+)\)$/)
		{
		    $optional = 1;
		    $group = $1;
		}

		my $g = &get_gid ($group);
		print "DEBUG: Config: $service->gid = ", $sconf->{$service}{'group'}, "\n" 
			if $DEBUG and defined $sconf->{$service}{'group'};
		if (!defined $g and !$optional)
		{
		    warn "Group \"$group\" in configuration file \"$dir/$file\" nonexistant. Skipping plugin.";
		    return undef;
		}
		elsif (!defined $g and $optional)
		{
		    print "DEBUG: Skipping \"$group\" (optional).\n" if $DEBUG;
		    next;
		}
		if (!defined $sconf->{$service}{'group'})
		{
		    $sconf->{$service}{'group'} = $g;
		}
		else
		{
		    $sconf->{$service}{'group'} .= " $g";
		}
	    }
	}
	elsif (/^\s*command\s+(.+)\s*$/)
	{
	    @{$sconf->{$service}{'command'}} = split (/\s+/, $1);
	}
	elsif (/^\s*host_name\s+(.+)\s*$/)
	{
	    $sconf->{$service}{'host_name'} = $1;
	}
	elsif (/^\s*timeout\s+(\d+)\s*$/)
	{
	    $sconf->{$service}{'timeout'} = $1;
	    print "DEBUG: $service: setting timeout to $1\n"
		if $DEBUG;
	}
	elsif (/^\s*(allow)\s+(.+)\s*$/ or /^\s*(deny)\s+(.+)\s*$/)
	{
	    push (@{$sconf->{$service}{'allow_deny'}}, [$1, $2]);
		print STDERR "DEBUG: Pushing allow_deny: $1, $2\n" if $DEBUG;
	}
	elsif (/^\s*env\s+([^=\s]+)\s*=\s*(.+)$/)
	{
	    $sconf->{$service}{'env'}{$1} = $2;
	    print "Saving $service->env->$1 = $2...\n" if $DEBUG;
	    warn "Warning: Deprecated format in \"$dir/$file\" under \"[$service]\" (\"env $1=$2\" should be rewritten to \"env.$1 $2\").";
	}
	elsif (/^\s*env\.(\S+)\s+(.+)$/)
	{
	    $sconf->{$service}{'env'}{$1} = $2;
	    print "Saving $service->env->$1 = $2...\n" if $DEBUG;
	}
	elsif (/^\s*(\w+)\s+(.+)$/)
	{
	    $sconf->{$service}{'env'}{"lrrd_$1"} = $2;
	    print "Saving $service->env->lrrd_$1 = $2...\n" if $DEBUG;
	    warn "Warning: Deprecated format in \"$dir/$file\" under \"[$service]\" (\"$1 $2\" should be rewritten to \"env lrrd_$1=$2\").";
	}
	elsif (/\S/)
	{
	    warn "Warning: Unknown config option in \"$dir/$file\" under \"[$service]\": $_";
	}

    }
    close (IN);

    return 1;
}

sub check_perms
{
    my $target = shift;
    my @stat;
    return undef if (!defined $target);
	return 1 if (!$paranoia);

    if (! -e "$target")
    {
	warn "Failed to check permissions on nonexistant target: \"$target\"";
	return undef;
    }

    @stat = stat ($target);
    if (!$stat[4] == 0 or
	($stat[5] != 0 and $stat[2] & 00020) or
	($stat[2] & 00002))
    {
	warn "Warning: \"$target\" has dangerous permissions (", sprintf ("%04o", $stat[2] & 07777), ").";
	return 0;
    }

    if (-f "$target") # Check dir as well
    {
	(my $dirname = $target) =~ s/[^\/]+$//;
	return &check_perms ($dirname);
    }

    return 1;
}

sub get_var_arr
{
    my $sconf   = shift;
    my $name    = shift;
    my $var     = shift;
    my $result  = [];

    if (exists $sconf->{$name}{$var})
    {
	push (@{$result}, $sconf->{$name}{$var});
    }

    foreach my $wildservice (grep (/\*$/, reverse sort keys %{$sconf}))
    {
	(my $tmpservice = $wildservice) =~ s/\*$//;
	next unless ($name =~ /^$tmpservice/);
	print STDERR "# Checking $wildservice...\n" if $DEBUG;

	if (defined $sconf->{$wildservice}{$var})
	{
	    push (@{$result}, $sconf->{$wildservice}{$var});
	    print STDERR ("DEBUG: Pushing: |", join (';', @{$sconf->{$wildservice}{$var}}), "|\n")
		if $DEBUG;
	}
    }
    return $result;
}

sub get_var
{
    my $sconf   = shift;
    my $name    = shift;
    my $var     = shift;
    my $env     = shift;

    if ($var eq 'env' and !defined $env)
    {
	%{$env} = ();
    }
    
    if ($var ne 'env' and exists $sconf->{$name}{$var})
    {
	return $sconf->{$name}{$var};
    }
    # Deciding environment
    foreach my $wildservice (grep (/\*$/, reverse sort keys %{$sconf}))
    {
	(my $tmpservice = $wildservice) =~ s/\*$//;
	next unless ($name =~ /^$tmpservice/);
	print "Checking $wildservice...\n" if $DEBUG;

	if ($var eq 'env')
	{
	    if (exists $sconf->{$wildservice}{'env'})
	    {
		foreach my $key (keys %{$sconf->{$wildservice}{'env'}})
		{
		    if (! exists $sconf->{$name}{'env'}{$key})
		    {
			$sconf->{$name}{'env'}{$key} = $sconf->{$wildservice}{'env'}{$key};
			print "Saving $wildservice->$key\n" if $DEBUG;
		    }
		}
	    }
	}
	else
	{
	    if (! exists $sconf->{$name}{$var} and
		    exists $sconf->{$wildservice}{$var})
	    {
		return ($sconf->{$wildservice}{$var});
	    }
	}
    }
    return $env;
}

1;

=head1 NAME

munin-node - A daemon to gather information in cooperation with the main
Munin program

=head1 SYNOPSIS

munin-node [--options]

=head1 OPTIONS

=over 5

=item B<< --config <configfile> >>

Use E<lt>fileE<gt> as configuration file. [/etc/munin/munin-node.conf]

=item B< --[no]paranoia >

Only run plugins owned by root. Check permissions as well. [--noparanoia]

=item B< --help >

View this help message.

=item B< --debug >

View debug messages.

=back

=head1 DESCRIPTION

Munin's node is a daemon that Munin connects to fetch data. This data is
stored in .rrd-files, and later graphed and htmlified. It's designed to
let it be very easy to graph new datasources.

Munin-node is a small perlscript listening to port 4949 using
Net::Server. It reads all the plugins in /etc/munin/plugins/ on startup.
The node accepts the following commands:

=over 5

=item B<< list [node] >>

list available plugins for host. If no hostname is specified, list plugins
on host running munin-node

=item B<< nodes >>

List nodes that has plugins in this munin-node.

=item B<< config <plugin> >>

output plugin configuration

=item B<< fetch <plugin> >>

output plugin values

=item B<< version >>

Print versionstring

=item B<< quit >>

disconnect

=back

=head2 Plugins

These plugins can be in you language of choice: bash, perl, python, C. The
plugins can be run in two modes: with and without the "config"-parameter. When
run with "config" as parameter, the plugin should output the configuration of
the graph. When run without parameters, the plugin should output just values

	# /etc/munin/plugins/load config
	host_name 
	graph_title Load average
	graph_args --base 1000 -l 0
	graph_vlabel load
	load.label load
	load.draw LINE2
	load.warning 10
	load.critical 120

	# /etc/munin/plugins/load
	load.value 0.43

For more information, see the documentation section at L<http://munin.sf.net/>.

=head1 FILES

	@@CONFDIR@@/munin-node.conf
	@@CONFDIR@@/plugins/*
	@@CONFDIR@@/plugin-conf.d/*
	@@STATEDIR@@/munin-node.pid
	@@LOGDIR@@/munin-node

=head1 VERSION

This is munin-node v@@VERSION@@

=head1 AUTHORS

Audun Ytterdal, Jimmy Olsen, and Tore Anderson.

=head1 BUGS

munin-node does, as of now, not check the syntax of the configuration file.

Please report other bugs in the bug tracker at L<http://munin.sf.net/>.

=head1 COPYRIGHT

Copyright © 2002 Audun Ytterdal, Jimmy Olsen, and Tore Anderson / Linpro AS.

This is free software; see the source for copying conditions. There is
NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.

This program is released under the GNU General Public License

=cut

# vim:syntax=perl ts=8