#!/usr/bin/perl -w

# check_disk_space.pl
# Send an email notice out when mounted file systems are past a given percentage.
#
# Perl v5.8.8
# Tested under RHEL4, RHEL5, and RHEL6
#
# When this script is run it will check the status of all mounted file systems
# using the df command and if the percentage is past the given critical set level
# will send out an email notice every time it is run. A set warning percentage 
# only send out an email every number_of_days_before_next_warning. 
# It keeps track of the number_of_days_before_next_warning using lock files. 
#
# The check_disk_space.xml config file should be in the same directory as the program, 
# and be given the same name if the program name is changed.
#
#check_disk_space.xml
# &lt; = <, &gt; = >
#-
# <config>
#  <warning_percent_used>90</warning_percent_used>
#  <critical_percent_used>99</critical_percent_used>
#  <number_of_days_before_next_warning>7</number_of_days_before_next_warning>
#  <warning_lock_directory>/home/<user>/</warning_lock_directory>
#  <hide_warning_lockfile>yes</hide_warning_lockfile>
#  <Include_Hostname_In_Subject>no</Include_Hostname_In_Subject>
#  <command_df>/bin/df</command_df>
#  <command_find>/bin/find</command_find>
#  <command_rm>/bin/rm</command_rm>
#  <command_date>/bin/date</command_date>
#  <command_hostname>/bin/hostname</command_hostname>
#  <command_sendmail>/usr/sbin/sendmail</command_sendmail>
#  <mail_to>user@mail.com</mail_to>
#  <mail_from>Disk Check &lt;user@system.com&gt;</mail_from>
#  <mail_subject_prefix>Disk Check</mail_subject_prefix>
#  <mail_subject_postfix></mail_subject_postfix>    
#  <mail_x_mailer>Disk Check</mail_x_mailer>
# </config>
#-
#
#  The following config toggles whether the host appears in the subject line.
#  A value of "yes" will trigger the hostname include.
#  <Include_Hostname_In_Subject>no</Include_Hostname_In_Subject>
#
# The following line troggles weather or not lock files are created with a
# hidden dot prefix. A value of "yes" will trigger the hidden file.
# <hide_warning_lockfile>yes</hide_warning_lockfile>
#
# The following line determins where the lock files will be placed. If left
# blank the lock files will be saved in the current directory. Be sure to
# end a directory path with a "/" in the config file.
#<warning_lock_directory>/home/<user>/</warning_lock_directory>
#
# This program doesn't require any special privlege accesses, except read/write
# access to the lockfile directory.
#
# Recommended Crontab Entry:
# # Check precentage of disk used every day and send out a email if critical levels are reached.
# 0 7 * * * cd /home/<user>/bin; /home/<user>/bin/check_disk_space.pl
#
# Script requirements: install XML Simple
# yum install perl-XML-Simple
# 
# History:
# ---------------------------------------------------------------------------
# 2014-02-24  kienenbe    Started, works.
#

use XML::Simple;
use File::Basename;
#use Data::Dumper;



#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
# Get the mount points from the df command.
#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

sub get_filesystem_data {
  my @mount_points;
  my $df_line;
  my $filesystem;
  my $junk;
  my $total_size;
  my $amount_used;
  my $amount_avalible;
  my $percent_used;

  my @df_output = `$command_df -lh`;

  foreach $df_line (@df_output) {
    if ($df_line =~ m#\d\%#) {
      #print "->$df_line";
    
      # Break out the needed data.
      ($percent_used,$filesystem) = split(/% /, $df_line);
      chomp $filesystem;
      ($junk,$total_size,$amount_used,$amount_avalible,$percent_used) = split(/\s+/, $percent_used);

      # Record the data for the filesystem mount point. 
      $filesystem_info{"$filesystem"}{"total_size"} = "$total_size";
      $filesystem_info{"$filesystem"}{"amount_used"} = "$amount_used";
      $filesystem_info{"$filesystem"}{"amount_avalible"} = "$amount_avalible";
      $filesystem_info{"$filesystem"}{"percent_used"} = "$percent_used";
    }
  }
}



#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
# Format the text report output for display.
#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

#       system.mysystem.org
#       Fri Feb 21 13:47:03 UTC 2014
# 
#  ---- Critical file system space at or above 45% ----
# 
#       Size  Used Avail  Use% Mounted on                                                  
#       1.8T  769G  973G   45% /mnt/backup                                               
#       1.1T  436G  550G   45% /data                                                        
# 
#  ---- Warning file system space at or above 8% ----
# 
#       Size  Used Avail  Use% Mounted on                                                  
#       485M   38M  422M    9% /boot     

sub format_report_output {
  $warning_duplicate_check  = 0;
  $critical_duplicate_check = 0;
  my $filename;
  

  # Cycle though each filesystem mount point.
  foreach my $filesystem (keys %filesystem_info) {
  
    if ($filesystem_info{"$filesystem"}{"percent_used"} >= $critical_percent_used) {
  
      if ($critical_duplicate_check eq 0) {
      
          # Only print the date and time stamp if this is the first warning check.
          if ($warning_duplicate_check eq 0) {
            $formated_report .= "\n      $Hostname\n      $TimeStamp\n";
          }
        $formated_report .= "\n ---- Critical file system space at or above ${critical_percent_used}% ----\n\n";
        $formated_report .= sprintf("     %5s %5s %5s %5s %-60s\n", "Size","Used","Avail","Use%","Mounted on");
        $critical_duplicate_check = 1;
      }
      $formated_report .= sprintf("     %5s %5s %5s %5s %-60s\n", $filesystem_info{$filesystem}{total_size},$filesystem_info{$filesystem}{amount_used},$filesystem_info{$filesystem}{amount_avalible},"$filesystem_info{$filesystem}{percent_used}%",$filesystem);
    }

    elsif ($filesystem_info{"$filesystem"}{"percent_used"} >= $warning_percent_used) {

      # Concert the file system mount point to a file name.
      $filename = &convert_filesystem_path_to_name($filesystem);
      
      # Remove warning locks for file system mount points past the number_of_days_before_next_warning
      &remove_warning_lockfile($filename);

      if (&check_for_warning_lockfile($filename)) {
        # Do nothing
      }
      else {
  
        if ($warning_duplicate_check eq 0) {

          # Only print the date and time stamp if this is the first critical check.
          if ($critical_duplicate_check eq 0) {
            $formated_report .= "\n      $Hostname\n      $TimeStamp\n";
          }
          $formated_report .= "\n ---- Warning file system space at or above ${warning_percent_used}% ----\n\n";
          $formated_report .= sprintf("     %5s %5s %5s %5s %-60s\n", "Size","Used","Avail","Use%","Mounted on");
          $warning_duplicate_check = 1;
        }
        $formated_report .= sprintf("     %5s %5s %5s %5s %-60s\n", $filesystem_info{$filesystem}{total_size},$filesystem_info{$filesystem}{amount_used},$filesystem_info{$filesystem}{amount_avalible},"$filesystem_info{$filesystem}{percent_used}%",$filesystem);

        # Create a warning lock file for the current file system mount point.
        &write_warning_lockfile($filename);
      }
    }
  }
}


#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
# Send out the email to the recipients.
#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

sub send_email_notice {

  # Send full report to recepiants(s)
    
  # Remove complaint about global empty vars such as ${mail_subject_postfix}
  no warnings 'uninitialized';

  if (  $warning_duplicate_check eq 1 or $critical_duplicate_check eq 1) {
    open (MAIL, "|$command_sendmail -t") || die "Can't open the mail binary: ${command_sendmail}!\n";
    print MAIL "X-Mailer: ${mail_x_mailer}\n";
    print MAIL "Return-Path: root\@${Hostname}\n";
    print MAIL "From: ${mail_from} <root\@${Hostname}>\n";
    print MAIL "To: ${mail_to}\n";
    if ($Include_Hostname_In_Subject eq "yes") {
      print MAIL "Subject: ${mail_subject_prefix}${Hostname}${mail_subject_postfix}\n\n";
    }
    else {	
      print MAIL "Subject: ${mail_subject_prefix}${mail_subject_postfix}\n\n";
    }
    print MAIL "\n${formated_report}\n\n";
    close (MAIL);
  }
}


#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
# Conver the file system mount point to a lockfile name.
#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

sub convert_filesystem_path_to_name {
  my $filesystem_path  = shift;
  my $lockfile_name;
  
  $filesystem_path =~ s#/#_#g;
  $filesystem_path =~ s# #_#g;
  
  if ($hide_warning_lockfile eq "yes") {
    $lockfile_name = "." . $program_name . "_warning_lock" . $filesystem_path;
  }
  else {
    $lockfile_name = $program_name . "_warning_lock" . $filesystem_path;
  }
  
  return ($lockfile_name);
  
}


#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
# Save the warning lockfile
#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

# Creates the locking file in the format of:
# / are converted to underscores for mount point.
# <.><progran name><_warning_lock><mountpoint>
#
# -rwxr-x---. 1 user user  9211 Feb 21 13:46 df.pl*
# -rw-rw-r--. 1 user user     0 Feb 21 13:47 .df_warning_lock_boot


sub write_warning_lockfile {
  my $lockfile_name  = shift;
  my $lockfile_directory = "./";

  # Check if the $warning_lock_directory has been set.
  # If so use it instead of the current directory.
  if ( $warning_lock_directory) {
   $lockfile_directory = $warning_lock_directory;
  }

  # Check for the warning lockfile.
  # If it already exists exit.
  if ( -e "${lockfile_directory}${lockfile_name}" ) {
    return;
  }
  
  open (WARNING_LOCKFILE, '>', ${lockfile_directory}.${lockfile_name}) or $formated_report .= "\nUnable to save warning lockfile for ${lockfile_directory}${lockfile_name}\n Warnings will be sent out every time the script runs.\n\n";
  close (WARNING_LOCKFILE); 
}


#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
# Check for the warning lockfile
#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

sub check_for_warning_lockfile {

  my $lockfile_name  = shift;
  my $lockfile_directory = "./";

  # Check if the $warning_lock_directory has been set.
  # If so use it instead of the current directory.
  if ( $warning_lock_directory) {
   $lockfile_directory = $warning_lock_directory;
  }

  # Check for the warning lockfile.
  if ( -e "${lockfile_directory}${lockfile_name}" ) {
    return 1;
  }
  else {
    return 0;
  }
}



#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
# Remove the warning lockfile
#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

sub remove_warning_lockfile {
  my $lockfile_name  = shift;
  my $lockfile_directory = "./";

  # Check if the $warning_lock_directory has been set.
  # If so use it instead of the current directory.
  if ( $warning_lock_directory) {
   $lockfile_directory = $warning_lock_directory;
  }

  # If the file doesn't exist just exit.
  if (! -e "${lockfile_directory}${lockfile_name}" ) {
    return;
  }
  
  # Remove the warning lockfile.
  `$command_find ${lockfile_directory}${lockfile_name} -mtime +${number_of_days_before_next_warning} -type f -exec $command_rm -f {} \\;`;
}
 
# Run the main routine.
&Start;

#>>>>>>>>>>>>>
#> Main Start 
#>>>>>>>>>>>>>

sub Start {

  #declare all major variables used in this subroutine.
  local (%filesystem_info, $TimeStamp, $Hostname, $formated_report, $warning_duplicate_check, $critical_duplicate_check, $program_name);
  
  # Obtain configuration from a file with a name inferred from this
  # script's name.
  ($program_name) = split(/\./, basename($0));
  my $program_full_name =basename($0);

  # if you don not wish to use XML::Simple comment out next line..
  $config = XMLin("${program_name}.xml", SuppressEmpty => 'undef');

  # if you don not wish to use XML::Simple configure variable directly here.
  # if you don't use the XML config file you must place a "\" in front of the
  # "@" in your email address so it is not interpreted as an array variable.
  # ex: local $mail_to                            = "vadapt.notice\@gmail.com";

  local $command_date                       = $config->{'command_date'};
  local $command_df                         = $config->{'command_df'};
  local $command_find                       = $config->{'command_find'};
  local $command_hostname                   = $config->{'command_hostname'};
  local $command_rm                         = $config->{'command_rm'};
  local $command_sendmail                   = $config->{'command_sendmail'};
  local $warning_percent_used               = $config->{'warning_percent_used'};
  local $critical_percent_used              = $config->{'critical_percent_used'};
  local $number_of_days_before_next_warning = $config->{'number_of_days_before_next_warning'};
  local $warning_lock_directory             = $config->{'warning_lock_directory'};
  local $hide_warning_lockfile              = $config->{'hide_warning_lockfile'};
  local $Include_Hostname_In_Subject        = $config->{'Include_Hostname_In_Subject'};
  local $mail_to                            = $config->{'mail_to'};
  local $mail_from                          = $config->{'mail_from'};
  local $mail_subject_prefix                = $config->{'mail_subject_prefix'};
  local $mail_subject_postfix               = $config->{'mail_subject_postfix'};
  local $mail_x_mailer                      = $config->{'mail_x_mailer'};


  # Get the hostname
  local $Hostname = `$command_hostname -f`;
  chomp $Hostname;

  # Get the date timestamp
  $TimeStamp = `$command_date`;
  chomp $TimeStamp;
  
  # Do the work
  &get_filesystem_data;
  &format_report_output;
  &send_email_notice;
  
  # uncomment to print report when run.
  #print $formated_report;

  #End the program
  exit;
}