#!/usr/bin/perl

# This is a Nagios-compatible script which checks all mounted filesystems--not just ZFS filesystems--to see
# if any are running dangerously low on space. It's generally bright enough to avoid weird mounts where
# free space checks don't apply, eg dev, tmpfs, CD or DVDs, and so forth.
#
# usage: 
#    check_all_disk_space [warnlevel] [critlevel]
#
# example:
#    root@banshee:~/check_all_disk_space 80 90
#    OK

# default levels: warn if a filesystem is 93% full, crit if it's 98% full
# default: warn 93%, crit 98%

my $warnlevel = .93;
my $critlevel = .98;

# accept warnlevel and critlevel as arguments if passed. Must be passed as decimals, eg 0.4 for 40%
if (defined $ARGV[0] && defined $ARGV[1] && $ARGV[0] >=0 && $ARGV[0] <=1 && $ARGV[1] >=0 && $ARGV[1] <=1) {
	$warnlevel = $ARGV[0];
	$critlevel = $ARGV[1];
}

my $msg,$warnfound,$critfound,$errfound;

# get standard df output, but skip the tmpfs and devtmpfs crap - this should leave us with
# nothing but disks.  we WILL also get nfs or other network filesystems here, since we
# didn't use the -l flag.  Feature, not bug.  also skip UDF so we don't check free space on CDs!
my @filesystems = `/bin/df -x tmpfs -x devtmpfs -x udf -x squashfs`;

# get rid of header line
shift @filesystems;

foreach my $fs (@filesystems) {
	chomp $fs;
	# compress space to make sure split works right
	$fs =~ s/ +/ /g;
	my ($dev,$space,$used,$available,$percent,$mounted) = split(' ',$fs);
	my $calcpercent = $used/$space;
	my $prettypercent = sprintf('%.1F%',($calcpercent * 100));
	if ($calcpercent > $critlevel) {
		$critfound = 1;
		$msg .= "$mounted: $prettypercent, ";
	} elsif ($calcpercent > $warnlevel) {
		$warnfound = 1;
		$msg .= "$mounted: $prettypercent, ";
	} elsif ($calcpercent < 0 || $calcpercent > 1) {
		$errfound = 1;
		$msg .= "$mounted: $prettypercent (WTF?), ";
	} 
}

$msg =~ s/, $//;
$msg .= "\n";

if ($critfound) {
	print "CRITICAL: $msg";
	exit 2;
} elsif ($warnfound) {
	print "WARNING: $msg";
	exit 1;
} elsif ($errfound) {
	print "ERROR: $msg";
	exit 3;
} else {
	print "OK\n";
	exit 0;
}


print "ERROR: $msg ?";
exit 3;