#!/usr/bin/perl -w

package main;

# RCS information (required by Perl::Critic)
# enable substitution with:
#   $ svn propset svn:keywords "Id Revision HeadURL Source Date"
#
#   $Id: check_dir 1259 2011-06-29 15:18:19Z corti $
#   $Revision: 1259 $
#   $HeadURL: https://svn.id.ethz.ch/nagios_plugins/check_dir/check_dir $
#   $Date: 2011-06-29 17:18:19 +0200 (Wed, 29 Jun 2011) $

use 5.00800;

use strict;
use warnings;

use English qw(-no_match_vars);

use Nagios::Plugin;
use Nagios::Plugin::Range;
use Nagios::Plugin::Getopt;
use Nagios::Plugin::Threshold;

our $VERSION = '3.0.0';

# IMPORTANT: Nagios plugins could be executed using embedded perl in this case
#            the main routine would be executed as a subroutine and all the
#            declared subroutines would therefore be inner subroutines
#            This will cause all the global lexical variables not to stay shared
#            in the subroutines!
#
# All variables are therefore declared as package variables...
#
## no critic (ProhibitPackageVars)
use vars qw(
  $n
  $plugin
  $options
  $status
  $info_string
  $threshold
);
## use critc

# the script is declared as a package so that it can be unit tested
# but it should not be used as a module
if ( !caller ) {
    run();
}

##############################################################################
# subroutines

##############################################################################
# Usage     : exit_with_error( $status, $message)
# Purpose   : if a plugin object is available exits via ->nagios_exit
#             otherwise prints to the shell and exit normally
# Returns   : n/a
# Arguments : n/a
# Throws    : n/a
# Comments  : n/a
# See also  : n/a
sub exit_with_error {

    my $status  = shift;
    my $message = shift;

    if ($plugin) {
        $plugin->nagios_exit( $status, $message );
    }
    else {
        #<<<
        print "Error: $message"; ## no critic (RequireCheckedSyscalls)
        #>>>
        exit $status;
    }

    return;

}

##############################################################################
# Usage     : max($i, $j)
# Purpose   : returns the maximum of two integers
# Returns   : the maximum of two integers
# Arguments : the integers to compare
# Throws    : n/a
# Comments  : n/a
# See also  : n/a
sub max {

    my ( $i, $j ) = @_;

    if ( $i > $j ) {
        return $i;
    }
    else {
        return $j;
    }

}

##############################################################################
# Usage     : verbose("some message string", $optional_verbosity_level);
# Purpose   : write a message if the verbosity level is high enough
# Returns   : n/a
# Arguments : message : message string
#             level   : options verbosity level
# Throws    : n/a
# Comments  : n/a
# See also  : n/a
sub verbose {

    # arguments
    my $message = shift;
    my $level   = shift;

    if ( !defined $message ) {
        exit_with_error( UNKNOWN,
            q{Internal error: not enough parameters for 'verbose'} );
    }

    if ( !defined $level ) {
        $level = 0;
    }

    if ( $options && $level < $options->verbose ) {
        print $message;    ## no critic (RequireCheckedSyscalls)
    }

    return;

}

##############################################################################
# Usage     : @files = get_entries("directory_name")
# Purpose   : reads the entries in the given directory
# Returns   : number of entries
# Arguments : dirname: the name of the directory to check
# Throws    : n/a
# Comments  : n/a
# See also  : n/a
sub get_entries {

    my $dirname = shift;

    #######################
    # get directory listing

    verbose "Opening $dirname\n", 1;

    my $DIR;
    opendir $DIR, $dirname
      or exit_with_error( UNKNOWN, "Can't open $dirname: $OS_ERROR" );

    # exclude .. and . from the count *and* recursion
    my @files = grep { $_ ne q{.} && $_ ne q{..} } readdir $DIR;

    closedir $DIR
      or exit_with_error( UNKNOWN, "Error closing $dirname: $OS_ERROR" );

    return @files;

}

##############################################################################
# Usage     : check_dir("directory_name")
# Purpose   : checks the number of files in the given directory
# Returns   : n/a
# Arguments : dirname: the name of the directory to check
# Throws    : n/a
# Comments  : n/a
# See also  : n/a
sub check_dir {

    my $dirname = shift;
    my $info;

    ####################################
    # check if the directory is readable

    $info = stat $dirname
      or exit_with_error( UNKNOWN, "Can't read stat for $dirname: $OS_ERROR" );

    my @files = get_entries($dirname);
    my $n     = @files;

    #################
    # Additional info
    verbose "Directory '$dirname' has $n files\n";

    #################
    # Output (status)

    $plugin->add_perfdata(
        label     => $dirname,
        value     => $n,
        uom       => q{},
        threshold => $threshold,
    );

    if ( defined $info_string ) {
        $info_string = "$info_string, $dirname=$n";
    }
    else {
        $info_string = "$dirname=$n";
    }

    $status = max( $status, $threshold->get_status($n) );

    ###########
    # Recursive
    if ( $options->get('recursive') ) {
        foreach my $file (@files) {
            if ( -d "$dirname/$file" ) {
                my $error = check_permissions("$dirname/$file");
                if ($error) {
                    exit_with_error( UNKNOWN, "Error: $error" );
                }
                check_dir("$dirname/$file");
            }
        }
    }

    return;
}

##############################################################################
# Usage     : check_permissions( $dirname )
# Purpose   : checks if the directory is readable
# Returns   : undef if OK or error message if the directory is not readable
# Arguments : dirname: the name of the directory to check
# Throws    : n/a
# Comments  : n/a
# See also  : n/a
sub check_permissions {

    my $dirname = shift;

    if ( !-d $dirname ) {
        return "$dirname is not a directory";
    }

    if ( !-r $dirname ) {
        return "$dirname is not readable";
    }

    if ( !-x $dirname ) {
        return "$dirname is not executable";
    }

    return;

}

##############################################################################
# Usage     : run();
# Purpose   : main method
# Returns   : n/a
# Arguments : n/a
# Throws    : n/a
# Comments  : n/a
# See also  : n/a
sub run {

    # initialization
    $plugin = Nagios::Plugin->new( shortname => 'CHECK_DIR' );

    $status = 0;

    ########################
    # Command line arguments

    $options = Nagios::Plugin::Getopt->new(
        usage   => 'Usage: %s [OPTIONS]',
        version => $VERSION,
        url     => 'https://trac.id.ethz.ch/projects/nagios_plugins',
        blurb   => 'cheks the number of files in one or more directories.',
    );

    $options->arg(
        spec     => 'dir|d=s@',
        help     => 'specify the directory (can be repeated)',
        required => 1,
    );

    $options->arg(
        spec     => 'critical|c=s',
        help     => 'specify the critical number (or range) of files',
        required => 1,
    );

    $options->arg(
        spec     => 'warning|w=s',
        help     => 'specify warning threshold (range) for the number of files',
        required => 1,
    );

    $options->arg(
        spec    => 'recursive|r',
        default => 0,
        help =>
          'perform recursive traversal (checks individual dirs not the total)',
    );

    $options->getopts();

    #############################
    # Sanity checks: command line

    my $critical_range =
      Nagios::Plugin::Range->parse_range_string( $options->get('critical') );
    if ( !$critical_range->is_set() ) {
        exit_with_error( UNKNOWN, 'Could not parse "critical"' );
    }

    my $warning_range =
      Nagios::Plugin::Range->parse_range_string( $options->get('warning') );
    if ( !$critical_range->is_set() ) {
        exit_with_error( UNKNOWN, 'Could not parse "warning"' );
    }

    $threshold = Nagios::Plugin::Threshold->set_thresholds(
        warning  => $warning_range,
        critical => $critical_range,
    );

    ##########################
    # Sanity checks: directory

    foreach my $dirname ( @{ $options->get('dir') } ) {
        my $error = check_permissions($dirname);
        if ($error) {
            exit_with_error( UNKNOWN, "Error: $error" );
        }
    }

    #############
    # Process dir

    foreach my $dirname ( @{ $options->get('dir') } ) {
        check_dir($dirname);
    }

    exit_with_error( $status, $info_string );

    return;

}

1;