#!/usr/bin/perl
#
# storage.monitor
#
# Use SNMP to get free disk space from a machine that implements HOSTMIB.
#
#   Exits with value of 1 if free space on any host drops below
#   the configured value, or exits with the value of 2 if
#   there is a "soft" error (SNMP library error, or could not get a
#   response from the server).
#
# Requirements:
#
#   Requires the UCD SNMP library and G.S. Marzot's Perl SNMP module.
#   (Avoid UCSD SNMP 3.6.1, it will cause segfaults.  Use 3.6.2+)
#
# Written by Peter Holzleitner
# based heavily on netappfree.monitor by Jim Trocki
#
#    Copyright (C) 2000, Peter Holzleitner
#    Copyright (C) 1998, Jim Trocki
#
#    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
#
#    Version 1.0.0
#
#
#use SNMP;
use SNMP_Session;
use Getopt::Long;

sub readcf;
sub toKB;

# load only the necessary MIBs:
$ENV{"MIBS"} = 'RFC1213-MIB:HOST-RESOURCES-MIB';

GetOptions (\%opt, "community=s", "timeout=i", "retries=i", "config=s", "list");

die "no host arguments\n" if (@ARGV == 0);

$RET = 0;
@ERRS = ();
@HOSTS = ();

$COMM    = $opt{"community"} || "public";
$TIMEOUT = $opt{"timeout"} * 1000 * 1000 || 5000000;
$RETRIES = $opt{"retries"} || 8;
$CONFIG  = $opt{"config"} || (-d "/etc/mon" ? "/etc/mon" : "/usr/lib/mon/etc")
	   . "/storage.cf";

$list = $opt{"list"};

($stDescr, $stUnit, $stSize, $stUsed) = (0..3);
$host = '';
$fsname = '';
$sizeK = 0;
$freeK = 0;
$OK = 0;

readcf ($CONFIG) || die "could not read config: $!\n";

foreach $host (@ARGV) {
    next if (!defined $FREE{$host});

    if (!defined($s = new SNMP::Session (DestHost => $host,
    		Timeout => $TIMEOUT, Community => $COMM,
		Retries => $RETRIES))) {
	$RET = ($RET == 1) ? 1 : 2;
	push (@HOSTS, $host);
	push (@ERRS, "could not create session to $host: " . $SNMP::Session::ErrorStr);
	next;
    }

    $v = new SNMP::VarList (
    	    ['hrStorageDescr'],  # 
    	    ['hrStorageAllocationUnits'],  # 
    	    ['hrStorageSize'],  #
    	    ['hrStorageUsed'],
    );

    while (defined $s->getnext($v)) {

	last if ($v->[$stDescr]->tag !~ /hrStorageDescr/);

#($stDescr, $stUnit, $stSize, $stUsed) = (0..3);

	$fsname =  $v->[$stDescr]->val;
	$unit   =  $v->[$stUnit]->val;
        $size   =  $v->[$stSize]->val;
	$used   =  $v->[$stUsed]->val;
        $freeK  = ($size - $used) * $unit / 1024;

	$OK = "(n/conf)";
	$needfreeK = $FREE{$host}{$fsname};
        if ( $needfreeK ) {
	    $OK = "OK";
	    if ( $freeK < $needfreeK ) {
		push (@HOSTS, $host);
		push (@ERRS, sprintf ("%s:%s: %1.1fMB free", $host, $fsname, $freeK));
		$OK = "LOW";
		$RET = 1;
	        }
	    }
        if($list)  {
            $sizeK  = $size * $unit / 1024;
	    write;
	    }
	} # while(getnext())

    if ($s->{ErrorNum}) {
	push (@HOSTS, $host);
	push (@ERRS, "could not get hrStorageDescr for $host: " . $s->{ErrorStr});
	$RET = ($RET == 1) ? 1 : 2;
	}
    }

if(!$list) {
    if ($RET) {
        print "@HOSTS\n";
	print "\n";
        print join("\n", @ERRS), "\n";
	}
    } # foreach(host)

exit $RET;


#
# read configuration file
#
sub readcf {
    my ($f) = @_;
    my ($l, $host, $filesys, $free);

    open (CF, $f) || return undef;
    while (<CF>) {
    	next if (/^\s*#/ || /^\s*$/);
	chomp;
	($host, $filesys, $free) = split;
	$filesys =~ tr/+/ /;    # + replaces space in config files
	if (!defined ($FREE{$host}{$filesys} = toKB ($free))) {
	    die "error free specification, config $f, line $.\n";
	}
    }
    close (CF);
}


sub toKB {
    my ($free) = @_;
    my ($n, $u);

    if ($free =~ /^(\d+\.\d+)(kb|mb|gb)$/i) {
        ($n, $u) = ($1, "\L$2");
    } elsif ($free =~ /^(\d+)(kb|mb|gb)$/i) {
        ($n, $u) = ($1, "\L$2");
    } else {
    	return undef;
    }

    return (int ($n * 1024))        if ($u eq "mb");
    return (int ($n * 1024 * 1024)) if ($u eq "gb");
    int ($n);
}


format STDOUT_TOP =
Host             File System                KB total     KB free   OK
----------------------------------------------------------------------------
.

format STDOUT =
@<<<<<<<<<<<<<<  @<<<<<<<<<<<<<<<<<<<<   @>>>>>>>>>>  @>>>>>>>>>>  @<<<<<<<
$host, $fsname, $sizeK, $freeK, $OK
.