#!/usr/bin/perl
#
# Monitor diskspace via SNMP
# (based on process.monitor by Brian Moore)
#
# Modified Oct 2001 by Dan Urist <durist@world.std.com>
# Changes: added usage, SNMP v.3 support, -T threshold option and
# unique-ified errors
#
# Modified Feb 2002 by Dan Urist <durist@world.std.com>
# Changes: added -C config file option; cleaned up code
#
# This script will exit with value 1 if host:community has dskErrorFlag
# set.  The summary output line will be the host names that failed
# and the disk information.  The detail lines are what UCD snmp returns
# for an dskErrMessage. ('/filesystem: less than WATERMARK free (= CURRENT)').
# If there is an SNMP error (either a problem with the SNMP libraries,
# or a problem communicating via SNMP with the destination host),
# this script will exit with a warning value of 2.
#
# If the -T threshold option is used, the script will exit with the
# highest disk percentage found that is over the threshold. The intent
# is to allow use with mon's "alert exit=value" parameter to allow for
# finer-grained alerts based on disk usage. If no disks are over the
# threshold, the script will exit with value 0; if an SNMP error
# occurs (and there are no other errors), the script will exit with
# value 2.
#
#    Copyright (C) 2001 SATOH Fumiyasu <fumiya@samba.gr.jp>
#
#    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; either version 2 of the License, or
#    (at your option) any later version.
#
#    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
#

use SNMP; 
use Getopt::Std;

$ENV{'MIBS'} = "UCD-SNMP-MIB";

getopts("hT:" . &SNMPconfig("getopts"));

my $VERSION = "0.3";
if( $opt_h || (scalar @ARGV == 0) ){
  print join("\n",
	     "$0 Version $VERSION; original version by SATOH Fumiyasu <fumiya\@samba.gr.jp>",
	     "SNMP v.3 support by Daniel J. Urist <durist\@world.std.com>.",
	     "\n",
	     );
  print "Usage: $0 OPTIONS host [host ...]\n";
  print "Options:\n";

  print join("\n\t",
	     "\t-h                    # Usage",
	     "[-T threshold]        # Exit value is highest disk % over threshold",
	     &SNMPconfig("usage"), "\n");
  exit 2;
}

# Get SNMP options
my %SNMPARGS = &SNMPconfig;

my $Threshold = $opt_T if defined($opt_T);

my $RETVAL = 0;
my %Failures;
my %Longerr;
my $Session;

foreach $host (@ARGV) {
  $Session = new SNMP::Session(
			       DestHost => $host,
			       %SNMPARGS,
			      );
  unless( defined($Session) ) {
    $RETVAL = 2 if $RETVAL == 0; # Other errors take precedence over SNMP error
    push @{$Failures{$host}}, "session error";
    $Longerr{"$host could not get SNMP session"} = "";
    next;
  }

  my $v = new SNMP::Varbind (["dskIndex"]);
  $Session->getnext ($v);

  while (!$Session->{"ErrorStr"} && $v->tag eq "dskIndex") {
    my @q = $Session->get ([
			    ["dskPath", $v->iid],	# 0
			    ["dskDevice", $v->iid],	# 1
			    ["dskMinimum", $v->iid],	# 2
			    ["dskMinPercent", $v->iid],	# 3
			    ["dskTotal", $v->iid],	# 4
			    ["dskAvail", $v->iid],	# 5
			    ["dskUsed", $v->iid],	# 6
			    ["dskPercent", $v->iid],	# 7
			    ["dskPercentNode", $v->iid],# 8
			    ["dskErrorFlag", $v->iid],	# 9
			    ["dskErrorMsg", $v->iid],	# 10
			   ]);
    last if ($Session->{"ErrorStr"});

    if( defined $Threshold ){
      if($q[7] > $Threshold){
	$RETVAL = $q[7] if $q[7] > $RETVAL;
	my ($t, $u, $a) = map { int($_/1024) } @q[4, 6, 5];
	push @{$Failures{$host}}, $q[0] . " ($q[7]%)";
	$Longerr{"$host:$q[0]($q[1]) total=$t used=$u($q[7]%) free=$a threshold=$Threshold%"} = "";
      }
    }
    elsif ($q[9] > 0) {
      $RETVAL = 1;	    
      my ($t, $u, $a) = map { int($_/1024) } @q[4, 6, 5];
      push @{$Failures{$host}}, $q[0] . " ($q[7]%)";
      $Longerr{"$host:$q[0]($q[1]) total=$t used=$u($q[7]%) free=$a err=$q[10]"} = "";
    }

    $Session->getnext ($v);
  }

  if ($Session->{"ErrorStr"}) {
    $RETVAL = 2 if $RETVAL == 0; # Other errors take precedence over SNMP error
    push(@{$Failures{$host}}, "SNMP error");
    $Longerr{"$host returned an SNMP error: " . $Session->{"ErrorStr"}} = "";
  }
}

if (scalar keys %Failures) {
  my $h;
  my @errs;
  foreach $h ( sort keys %Failures ){
    push( @errs, $h . ':' . join(',', @{$Failures{$h}}) );
  }
  print join(";", @errs), "\n\n";

  print join ("\n", sort keys %Longerr), "\n";
}

exit $RETVAL;

#
# Manage the standard SNMP options
# Arguments are same as netsnmp utils
#
# If called with "getopts", returns a string for "getopts"
# If called with "usage", returns an array of usage information
# Otherwise, returns a hash of SNMP config vars
#
# Overloading this sub like this is kinda hoakey,
# but keeps everything in one place
sub SNMPconfig {
  my($action) = @_;

  if($action eq "getopts"){
    return "C:t:r:p:v:u:l:A:e:E:n:a:x:X:";
  }
  elsif($action eq "usage"){
    return(
	   "[-C configfile]       # SNMP vars config file",
	   "[-t Timeout]          # Timeout in ms (default: 1000000)",
	   "[-r Retries]          # Retries before failure (default: 5)",
	   "[-p RemotePort]       # Remote UDP port (default 161)",
	   "[-v Version]          # 1,2,2c or 3 (default: 1)",
	   "[-c Community]        # v.1,2,2c Community Name (default: public)",
	   "[-u SecName]          # v.3 Security Name (default: initial)",
	   "[-l SecLevel]         # v.3 Security Level (default: noAuthNoPriv)",
	   "[-A AuthPass]         # v.3 Authentication Passphrase (default: none)",
	   "[-e SecEngineId]      # v.3 security engineID (default: none)",
	   "[-E ContextEngineId]  # v.3 context engineID (default: none)",
	   "[-n Context]          # v.3 context name (default: none)",
	   "[-a AuthProto]        # authentication protocol (MD5|SHA; default MD5)",
	   "[-x PrivProto]        # privacy protocol (DES)",
	   "[-X PrivPass]         # privacy passphrase (default: none)",
	  );
  }

  # Read config file
  my %Conf;
  if($opt_C){
    unless( open(CONF, $opt_C) ){
      print "$0: Could not open config file $opt_C\n";
      exit 2;
    }
    my $line;
    my @fields;
    foreach $line (<CONF>){
      chomp $line;
      @fields = split(/=/, $line);
      $Conf{ lc $fields[0] } = $fields[1];
    }
    close CONF;
  }

  my %SNMPARGS;

  # Common options
  $SNMPARGS{Timeout} = $opt_t || $Conf{timeout} || 1000000;
  $SNMPARGS{Retries} = $opt_r || $Conf{retries} || 5;
  $SNMPARGS{RemotePort} = $opt_p || $Conf{remoteport} || 161;
  $SNMPARGS{Version} = $opt_v || $Conf{version} || 1;

  # v. 3 options
  if ($SNMPARGS{Version} eq "3"){
    $SNMPARGS{SecName} = $opt_u || $Conf{secname} || 'initial';
    $SNMPARGS{SecLevel} = $opt_l || $Conf{seclevel} || 'noAuthNoPriv';
    $SNMPARGS{AuthPass} = $opt_A || $Conf{authpass} || '';
    $SNMPARGS{SecEngineId} = $opt_e || $Conf{secengineid} || '';
    $SNMPARGS{ContextEngineId} = $opt_E || $Conf{contextengineid} || '';
    $SNMPARGS{Context} = $opt_n || $Conf{context} || '';
    $SNMPARGS{AuthProto} = $opt_a || $Conf{authproto} || '';
    $SNMPARGS{PrivProto} = $opt_x || $Conf{privproto} || '';
    $SNMPARGS{PrivPass} = $opt_X || $Conf{privpass} || '';
  }
  # v. 1,2 options
  else{
    $SNMPARGS{Community} = $opt_c || $Conf{community} || 'public';
  }

  return %SNMPARGS;
}