#!/usr/bin/perl -w

# check_samhain.pl - check to see how many policy violations are reported
#   by the samhain file integrity checker.
#
# Copyright Rainer Wichmann (2004)
# Copyright Martin Zobel-Helas (2008)
#
# License Information:
# 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., 675 Mass Ave, Cambridge, MA 02139, USA.
#
############################################################################

# -------------------------------------------------------------------[ Uses ]--

use strict;
use Getopt::Long;
use vars qw($PROGNAME $SAMHAIN $opt_V $opt_h $opt_v $verbose $opt_w $opt_c $opt_t $status $msg $state $retval);
use lib "/usr/lib/nagios/plugins";
use utils qw(%ERRORS &print_revision);

#my $TIMEOUT = 15;
#my %ERRORS=('OK'=>0,'WARNING'=>1,'CRITICAL'=>2,'UNKNOWN'=>3,'DEPENDENT'=>4);
#sub print_revision ($$);

# ----------------------------------------------------[ Function Prototypes ]--

sub print_help ();
sub print_usage ();
sub process_arguments ();

# ------------------------------------------------------------[ Environment ]--

$ENV{'PATH'}='';
$ENV{'BASH_ENV'}=''; 
$ENV{'ENV'}='';

# -----------------------------------------------------------------[ Global ]--

$PROGNAME = "dsa-check-samhain";
$SAMHAIN = "/usr/sbin/samhain"; 

# ----------------------------------------------------------------[ options ]--

Getopt::Long::Configure('bundling');
$status = process_arguments();
if ($status){
	print "ERROR: processing arguments\n";
	exit $ERRORS{"UNKNOWN"};
}

# ----------------------------------------------------------------[ timeout ]--

$SIG{'ALRM'} = sub {
	print ("ERROR: timed out waiting for $SAMHAIN\n");
	exit $ERRORS{"WARNING"};
};
alarm($opt_t);

# ----------------------------------------------------------[ start samhain ]--

if ( defined $SAMHAIN && -x $SAMHAIN ) {
    if (! open (SHPIPE, "/usr/bin/sudo $SAMHAIN -t check --foreground -p err -s none -l none -m none 2>&1 | " ) ) {
	print "ERROR: could not popen $SAMHAIN \n";
	exit $ERRORS{'UNKNOWN'};
    }
}else{
    print "ERROR: Could not find samhain executable!\n";
    exit $ERRORS{'UNKNOWN'};
}

# ---------------------------------------------------------[ read from pipe ]--

$status = 0;

while (<SHPIPE>) {
    if (/POLICY/) {
	++$status;
	print $_ if $verbose;
    }
}    

if ($status < $opt_w) {
    $msg = "OK: $status policy violations (threshold $opt_w/$opt_c)";
    $state = $ERRORS{'OK'};
} elsif ($status >= $opt_w  && $status < $opt_c) {
    $msg = "WARNING: $status policy violations (threshold w=$opt_w)";
    $state = $ERRORS{'WARNING'};
} else {
    $msg = "CRITICAL: $status policy violations (threshold w=$opt_w)";
    $state = $ERRORS{'CRITICAL'};
}

# -------------------------------------------------------------[ close pipe ]--

close (SHPIPE);
 
# declare an error if we also get a non-zero return code from samhain

if ( $? ) {
    $retval = $? / 256;
    if ( $! ) {
      print "Error closing $SAMHAIN: $!\n" if $verbose;
    } else {
      print "$SAMHAIN returned exit status $retval\n" if $verbose;
    }
    if ($state == $ERRORS{"CRITICAL"}) { 
	$state = $ERRORS{"CRITICAL"}; 
    } else {
        print "ERROR: $SAMHAIN exit status $retval\n";
        exit $ERRORS{'UNKNOWN'};
    }
}

# -------------------------------------------------------------------[ exit ]--

print "$msg | 'policy violations'=$status;$opt_w;$opt_c\n";
exit $state;


# ------------------------------------------------------------[ Subroutines ]--

sub process_arguments(){
    GetOptions
	("V"   => \$opt_V, "version"	=> \$opt_V,
	 "h"   => \$opt_h, "help"	=> \$opt_h,
	 "v"   => \$opt_v, "verbose"    => \$opt_v,
	 "w=i" => \$opt_w, "warning=i"  => \$opt_w,   
	 "c=i" => \$opt_c, "critical=i" => \$opt_c,	
	 "t=i" => \$opt_t, "timeout=i"  => \$opt_t 
	 );
    
    if ($opt_V) {
	print_revision($PROGNAME,'$Revision: 1.0 $ ');
	exit $ERRORS{'OK'};
    }
    
    if ($opt_h) {
	print_help();
	exit $ERRORS{'OK'};
    }
    
    if (defined $opt_v ){
	$verbose = $opt_v;
    }

    unless (defined $opt_t) {
	$opt_t = $utils::TIMEOUT ;	# default timeout
	# $opt_t = $TIMEOUT ;
    }
    
    unless (defined $opt_w) {
	$opt_w = 1;
    }
    
    unless (defined $opt_c) {
	$opt_c = 1;
    }
    
    if ( $opt_w > $opt_c) {
	print "Warning cannot be greater than Critical!\n";
	exit $ERRORS{'UNKNOWN'};
    }
    
    return $ERRORS{'OK'};
}

sub print_usage () {
    print "Usage: $PROGNAME [-w <warn>] [-c <crit>] [-t <timeout>]\n";
}

sub print_help () {
    print_revision($PROGNAME, '$Revision: 1.0 $');
    print "Copyright (c) 2004 Rainer Wichmann

This plugin checks the number of policy violations reported by the
samhain file intgrity checker

";
    print_usage();
    print "
-w, --warning=INTEGER
   Minimum number of policy violations for which a WARNING status will result
-c, --critical=INTEGER
   Minimum number of policy violations for which a CRITICAL status will result
-t, --timeout=SECONDS
   The number of seconds after which a the plugin will timeout
-v, --verbose
   Verbose output
-h, --help
   Show this help message
-V, --version
   Show the version of the plugin

";
}

#sub print_revision ($$) {
#        my $commandName = shift;
#        my $pluginRevision = shift;
#        $pluginRevision =~ s/^\$Revision: //;
#        $pluginRevision =~ s/ \$\s*$//;
#        print "$commandName (samhain 2.2.3) $pluginRevision\n";
#}