#!/usr/bin/perl
# Copyright (C) 2015
# 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 3 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA

# Author Bryan Christensen

use warnings;
use strict;
use Getopt::Long;
use Fcntl qw(:DEFAULT :flock);

my %opt = (
    'start'        => 0,
    'stop'         => 0,
    'check'        => 0,
    'print'        => 0,
    'loadavg'      => 0,
    'help'         => 0,
    'network'      => 0,
    'io'           => 0,
    'print_cpu'    => 1,
    'print_memory' => 1,
    'interval'     => 10,
    'loadavg'      => 0,
    'dir'          => '/root/system-snapshot',
    'verbose'      => '0',
    'max-lines'    => '20',
    'line_length'  => '145',
    'pidfile'      => '/var/run/sys-snap.pid',
);

GetOptions(
    \%opt,
    'help|h+',
    'print',
    'network',
    'start',
    'stop',
    'check|c',
    'loadavg',
    'io',
    'cpu!'           => \$opt{'print_cpu'},
    'mem!'           => \$opt{'print_memory'},
    'interval|i=i'   => \$opt{'interval'},
    'dir|d=s'        => \$opt{'dir'},
    'verbose|v!'     => \$opt{'verbose'},
    'max-lines|ml=i' => \$opt{'max-lines'},
) or usage();

########################################################
# start of parameters that don't need time
########################################################

if ( $opt{'help'} ) {
    usage();
    exit;
}
elsif ( $opt{'start'} ) {
    run_install();
    exit;
}
elsif ( $opt{'stop'} ) {
    stop_syssnap();
    exit;
}
elsif ( $opt{'check'} ) {
    check_status();
    exit;
}

########################################################
# start of parameters that need time
########################################################

# two extra parameters are expected if you are using options that need time
if ( @ARGV < 2 ) {
    usage();

    #print "No time range specified\n";
    exit();
}
elsif ( @ARGV > 3 ) {
    print "Too many unknown parameters\n";
    exit;
}
elsif ( @ARGV == 2 ) {
    $opt{'time1'} = $ARGV[0];
    $opt{'time2'} = $ARGV[1];
}

if ( $opt{'loadavg'} ) {
    loadavg( \%opt );
    exit;
}

if ( $opt{'io'} ) {
    snap_io( \%opt );
    exit;
}

if ( $opt{'print'} ) {
    snap_print_range( \%opt );
    exit;
}

if ( $opt{'network'} ) {
    snap_network( \%opt );
    exit;
}

# I don't think the logic flow should ever hit this, but just in case
usage();
exit;

sub snap_network {
    my %opt          = %{ shift @_ };
    my $time1        = $opt{'time1'};
    my $time2        = $opt{'time2'};
    my $snapshot_dir = $opt{'dir'};
    my $detail_level = $opt{'verbose'};
    my $max_lines    = $opt{'max-lines'};
    my $print_cpu    = $opt{'print_cpu'};
    my $print_memory = $opt{'print_memory'};

    # old school 80 is standard, but 145 works well with 1366 width monitor
    my $line_length = $opt{'line_length'};

    #root_dir is legacy param, will remove later
    my $root_dir = "";

    # the default formatting where the process ID is added needs 16 lines
    # subtracting 16 here will make the specified width more "true"
    $line_length = $line_length - 16;

    module_sanity_check();
    eval("use Time::Piece;");
    if ($@) {
        print "***\nCould not install Time::Piece - try manually installing.\n***\n";
        exit;
    }

    my ( $time1_hour, $time1_minute, $time2_hour, $time2_minute ) = &parse_check_time( $time1, $time2 );
    my @snap_log_files = &get_range( $root_dir, $snapshot_dir, $time1_hour, $time1_minute, $time2_hour, $time2_minute );

    my %ip_connections;
    my ( %localip, %foreignip );

    #print "Time\t1min-avg\t5min-avg\t15min-avg\n";
    foreach my $file_name (@snap_log_files) {

        open( my $FILE, "<", $file_name ) or next;    #die "Couldn't open file: $!";
        my $string = join( "", <$FILE> );
        close($FILE);

        my @lines;

        # reading line by line to split the sections might be faster
        my $matchme = "^Active Internet connections [^\n]+\n";

        #my $matchme = "^Process List:\n\nUSER[^\n]+COMMAND\n";
        if ( $string =~ /$matchme(.*)\nActive UNIX domain sockets \(servers and established\)/sm ) {
            my $baseString = $1;
            @lines = split( /\n/, $baseString );
        }

        # could add ports in the future and connection state
        # should skip listen and time_wait entries
        foreach my $line (@lines) {
            if ( $line =~ /[a-z]{3}\s+\d+\s+\d+\s+(\d+\.\d+\.\d+\.\d+):\d+\s+(\d+\.\d+\.\d+\.\d+):\d+\s+(?!TIME_WAIT)/ ) {
                if ( $ip_connections{$1}{$2} ) {
                    $ip_connections{$1}{$2} += 1;
                }
                else {
                    $ip_connections{$1}{$2} = 1;
                }
            }
        }
    }

    foreach my $localip ( keys %ip_connections ) {
        my @sorted_ip = sort { $ip_connections{$localip}{$b} <=> $ip_connections{$localip}{$a} } keys %{ $ip_connections{$localip} };
        print "$localip: \n";
        for (@sorted_ip) {
            printf "\t%-15s %-8d\n", $_, $ip_connections{$localip}{$_};
        }
        print "\n";
    }
}

sub usage {
    my $text = <<"ENDTXT";
USAGE:
./sys-snap.pl [options]
    --start : Creates, disowns, and drops 'sys-snap.pl --start' process into the background
    --stop : stops sys-snap after confirming PID info
    --check : Checks if sys-snap is running
    --print <start-time end-time> : Where time HH:MM, prints basic usage by default
    --network <start-time end-time> : Prints IP connections durring time range
    --v | v : verbose output from --print
    --max-lines : max number of processes printed per mem/cpu section, default is 20
    --ll : line length, default is 145
    --no-cpu | --nc : skips CPU output
    --no-mem | --nm : skips memory output
    --loadavg <start-time end-time>: Where time HH:MM, prints load average for time period - default 10 min interval
    --dir : specifies a different sys-snap folder for --print and --loadavg

ENDTXT

    print $text;
    exit;
}

sub snap_io {
    eval("use Time::Piece;");
    my %opt          = %{ shift @_ };
    my $time1        = $opt{'time1'};
    my $time2        = $opt{'time2'};
    my $interval     = $opt{'interval'};
    my $snapshot_dir = $opt{'dir'};

    #root_dir is legacy param, will remove later
    my $root_dir = "";

    if ( $interval > 60 || $interval < 0 ) {
        $interval = 10;
    }

    my ( $time1_hour, $time1_minute, $time2_hour, $time2_minute ) = &parse_check_time( $time1, $time2 );
    my @snap_log_files = &get_range( $root_dir, $snapshot_dir, $time1_hour, $time1_minute, $time2_hour, $time2_minute );

    print "avg-cpu:\t%user\t%nice\t%system\t%iowait\t%steal\t%idle\n";
    foreach my $file_name (@snap_log_files) {

        # load information is currently printed to the first line
        # only need to read first line
        open( my $FILE, "<", $file_name ) or next;    #die "Couldn't open file: $!";
                                                      #my $string = <$FILE>;
        my $string = join( "", <$FILE> );
        my ($min) = $string =~ m{^\d+\s+\d+\s+(\d+)\s+Load Average:}g;

        #print "$min\n";
        close($FILE);

        my @lines;
        if ( $string =~ /^IO wait:\n(.*)\nMYSQL Processes:$/sm ) {
            my $baseString = $1;
            @lines = split( /\n/, $baseString );
        }

        foreach my $line (@lines) {
            my ( $io_user, $nice, $io_system, $io_wait, $steal, $idle );
            ( $io_user, $nice, $io_system, $io_wait, $steal, $idle ) = $line =~ m{^\s+(\d+\.\d+)\s+(\d+\.\d+)\s+(\d+\.\d+)\s+(\d+\.\d+)\s+(\d+\.\d+)\s+(\d+\.\d+)};
            if ( defined $io_user && ( $min % $interval == 0 ) ) {
                print "\t\t$io_user\t$nice\t$io_system\t$io_wait\t$steal\t$idle\n";
            }
        }
    }
    return;
}

sub loadavg {
    eval("use Time::Piece;");
    my %opt          = %{ shift @_ };
    my $time1        = $opt{'time1'};
    my $time2        = $opt{'time2'};
    my $interval     = $opt{'interval'};
    my $snapshot_dir = $opt{'dir'};

    #root_dir is legacy param, will remove later
    my $root_dir = "";

    if ( $interval > 60 || $interval < 0 ) {
        $interval = 10;
    }

    my ( $time1_hour, $time1_minute, $time2_hour, $time2_minute ) = &parse_check_time( $time1, $time2 );

    my @snap_log_files = &get_range( $root_dir, $snapshot_dir, $time1_hour, $time1_minute, $time2_hour, $time2_minute );

    print "Time\t1min-avg\t5min-avg\t15min-avg\n";

    foreach my $file_name (@snap_log_files) {

        # load information is currently printed to the first line
        # only need to read first line
        open( my $FILE, "<", $file_name ) or next;    #die "Couldn't open file: $!";
        my $string = <$FILE>;
        close($FILE);

        my ( $avg1min, $avg5min, $avg15min, $hour, $min );
        ( $hour, $min, $avg1min, $avg5min, $avg15min ) = $string =~ m{^\d+\s+(\d+)\s+(\d+)\s+Load Average: (\d+\.\d+)\s(\d+\.\d+)\s(\d+\.\d+)\s.*$};

        if ( defined $hour && defined $min & defined $avg1min && defined $avg5min && defined $avg15min && ( $min % $interval == 0 ) ) {
            $min = "0" . $min if ( $min =~ m{^\d$} );
            print "$hour:$min\t$avg1min\t\t$avg5min\t\t$avg15min\n";
        }
    }
    return;
}

sub stop_syssnap {
    if ( my $pid = check_status() ) {
        print "Stop this process (y/n)?:";
        my $choice = "0";
        $choice = <STDIN>;
        while ( $choice !~ /[yn]/i ) {
            print "Stop this process (y/n)?:";
            $choice = <STDIN>;
            chomp($choice);
        }
        if ( $choice =~ /[y]/i ) {
            print "Stopping $pid\n";
            kill 9, $pid;
            unlink $opt{'pidfile'};
            exit;
        }
        else { print "Exiting...\n"; exit; }
    }
    return;
}

sub check_status {
    my $pid;
    my $pidfh;
    my $pidfile = $opt{'pidfile'};
    my $status  = 0;

    sysopen( $pidfh, $pidfile, O_RDWR | O_CREAT )
      or die "Could not open $pidfile: $!\n";
    if ( flock( $pidfh, LOCK_NB | LOCK_EX ) ) {
        print "Sys-snap not currently running.\n";
        flock( $pidfh, LOCK_UN )
          or die "Problem releasing lock on '$pidfile': $!\n";
        $status = 0;
    }
    else {
        print "Sys-snap is running, PID: ";
        while ( $pid = <$pidfh> ) {
            print "'$pid'\n";
            $status = $pid;
        }
    }
    return $status;
}

sub parse_check_time {

    my $time1 = shift;
    my $time2 = shift;

    if ( !defined $time1 || !defined $time2 ) { print "Need 2 parameters, \"./snap-print start-time end-time\"\n"; exit; }

    my ( $time1_hour, $time1_minute, $time2_hour, $time2_minute );

    if ( ( $time1_hour, $time1_minute ) = $time1 =~ m{^(\d{1,2}):(\d{2})$} ) {
        if ( $time1_hour >= 0 && $time1_hour <= 23 && $time1_minute >= 0 && $time1_minute <= 59 ) {

            #print "$time1_hour $time1_minute\n";
        }
        else { print "Fail: Fictitious time.\n"; exit; }

    }
    else { print "Fail: Could not parse start time\n"; exit; }

    if ( ( $time2_hour, $time2_minute ) = $time2 =~ m{(\d{1,2}):(\d{2})} ) {
        if ( $time2_hour >= 0 && $time2_hour <= 23 && $time2_minute >= 0 && $time2_minute <= 59 ) {

            #print $time2_hour $time2_minute\n";
        }
        else { print "Fail: Fictitious time.\n"; exit; }

    }
    else { print "Fail: Could not parse end time\n"; exit; }

    if ( defined $time1_hour && defined $time2_hour ) { return ( $time1_hour, $time1_minute, $time2_hour, $time2_minute ); }
    return 0;
}

sub snap_print_range {
    my %opt          = %{ shift @_ };
    my $time1        = $opt{'time1'};
    my $time2        = $opt{'time2'};
    my $snapshot_dir = $opt{'dir'};
    my $detail_level = $opt{'verbose'};
    my $max_lines    = $opt{'max-lines'};
    my $print_cpu    = $opt{'print_cpu'};
    my $print_memory = $opt{'print_memory'};

    # old school 80 is standard, but 145 works well with 1366 width monitor
    my $line_length = $opt{'line_length'};

    #root_dir is legacy param, will remove later
    my $root_dir = "";

    # the default formatting where the process ID is added needs 16 lines
    # subtracting 16 here will make the specified width more "true"
    $line_length = $line_length - 16;

    if ( !defined $time1 || !defined $time2 ) { print "Need 2 parameters, \"./snap-print start-time end-time\"\n"; exit; }

    module_sanity_check();
    eval("use Time::Piece;");
    if ($@) {
        print "***\nCould not install Time::Piece - try manually installing.\n***\n";
        exit;
    }

    use Time::Seconds;

    # not using this yet, but if we parse a range of data that crosses this file the resulting data is noncontigous
    # and might be misleading. printing a warning might be apropriate in this scenario or having some other flag
    # to indicate this has happened
    #my $newest_file = qx(ls -la ${root_dir}/system-snapshot/current);

    my ( $time1_hour, $time1_minute, $time2_hour, $time2_minute ) = &parse_check_time( $time1, $time2 );

    # get the files we want to read
    my @snap_log_files = &get_range( $root_dir, $snapshot_dir, $time1_hour, $time1_minute, $time2_hour, $time2_minute );

    my ( $tmp1, $tmp2 ) = &read_logs( \@snap_log_files );

    # users cumulative CPU and Mem score
    my %basic_usage = %$tmp1;

    #raw data from logs
    my %process_list_data = %$tmp2;

    # weighted process & memory
    my %users_wcpu_process;
    my %users_wmemory_process;

    if ( $detail_level == 0 ) { &run_basic( \%basic_usage, $print_cpu, $print_memory ); exit }

    # adding up memory and CPU usage per user's process
    foreach my $user ( sort keys %process_list_data ) {
        foreach my $process ( sort keys %{ $process_list_data{$user} } ) {

            $users_wcpu_process{$user}{$process}    += $process_list_data{$user}{$process}{'cpu'};
            $users_wmemory_process{$user}{$process} += $process_list_data{$user}{$process}{'memory'};
        }
    }

    my $sort_param;
    if   ($print_cpu) { $sort_param = "cpu"; }
    else              { $sort_param = "memory"; }

    foreach my $user ( sort { $basic_usage{$b}->{$sort_param} <=> $basic_usage{$a}->{$sort_param} } keys %basic_usage ) {

        printf "user: %-15s", $user;

        my $num_lines = 0;
        if ($print_cpu) {

            my @sorted_cpu = sort { $users_wcpu_process{$user}{$b} <=> $users_wcpu_process{$user}{$a} } keys %{ $users_wcpu_process{$user} };

            printf "\n\tcpu-score: %-10.2f\n", $basic_usage{$user}{'cpu'};
            for (@sorted_cpu) {
                printf "\t\tC: %4.2f proc: ", $users_wcpu_process{$user}{$_};
                print substr( $_, 0, $line_length ) . "\n";
                if   ( $num_lines >= $max_lines - 1 ) { last; }
                else                                  { $num_lines += 1; }
            }
        }

        $num_lines = 0;
        if ($print_memory) {

            my @sorted_mem = sort { $users_wmemory_process{$user}{$b} <=> $users_wmemory_process{$user}{$a} } keys %{ $users_wmemory_process{$user} };

            printf "\n\tmemory-score: %-11.2f\n", $basic_usage{$user}{'memory'};
            for (@sorted_mem) {
                printf "\t\tM: %4.2f proc: ", $users_wmemory_process{$user}{$_};
                print substr( $_, 0, $line_length ) . "\n";
                if   ( $num_lines >= $max_lines - 1 ) { last; }
                else                                  { $num_lines += 1; }
            }
        }
        print "\n";
    }
    exit;
}

## should be rewritten to take parameters of log subsections to be read
# returns hash of hashes
sub read_logs {

    my $tmp            = shift;
    my @snap_log_files = @$tmp;

    my %process_list_data;
    my %basic_usage;

    foreach my $file_name (@snap_log_files) {

        my @lines;

        open( my $FILE, "<", $file_name ) or next;    #die "Couldn't open file: $!";
        my $string = join( "", <$FILE> );
        close($FILE);

        # reading line by line to split the sections might be faster
        my $matchme = "^Process List:\n\nUSER[^\n]+COMMAND\n";
        if ( $string =~ /^$matchme(.*)\nNetwork Connections\:$/sm ) {
            my $baseString = $1;
            @lines = split( /\n/, $baseString );
        }

        foreach my $l (@lines) {
            my ( $user, $cpu, $memory, $command );
            ( $user, $cpu, $memory, $command ) = $l =~ m{^(\w+)\s+\d+\s+(\d{1,2}\.\d)\s+(\d{1,2}\.\d).*\d{1,2}:\d{2}\s+(.*)$};

            if ( defined $user && defined $cpu && defined $memory && defined $command ) {

                if ( $user !~ m/[a-zA-Z0-9_\.\-]+/ ) { next; }
                if ( $cpu !~ m/[0-9\.]+/ && $memory !~ m/[0-9\.]+/ ) { next; }
                $basic_usage{$user}{'memory'} += $memory;
                $basic_usage{$user}{'cpu'}    += $cpu;

                # agrigate hash? of commands - roll object

                # if the process is the same, accumulate it, if not create it
                # assuming if we have a memory value for a command, we should have a cpu value - nothing can ever go wrong here :smiley face:
                if ( defined $process_list_data{$user}{$command}{'memory'} ) {
                    $process_list_data{$user}{$command}{'memory'} += $memory;
                    $process_list_data{$user}{$command}{'cpu'}    += $cpu;
                }
                else {
                    $process_list_data{$user}{$command}{'cpu'}    = $cpu;
                    $process_list_data{$user}{$command}{'memory'} = $memory;
                }
            }
        }
    }
    return ( \%basic_usage, \%process_list_data );
}

# returns ordered array of stings that represent file location
# could create $accuracy variable to run modulo integers for faster processing at expense of accuracy
sub get_range {

    my $root_dir     = shift;
    my $snapshot_dir = shift;
    my $time1_hour   = shift;
    my $time1_minute = shift;
    my $time2_hour   = shift;
    my $time2_minute = shift;
    my $time1        = "$time1_hour:$time1_minute";
    my $time2        = "$time2_hour:$time2_minute";

    my @snap_log_files;
    my ( $file_hour, $file_minute );

    # Even if we want to ignore the date, Time::Piece will create one. This is probably easier than rolling a custom time cycle for over night periods such as 23:57 0:45,
    # and should make modification easier if longer date ranges are added too.
    # Mind the date format 'DAY MONTH YEAR(XXXX)'
    my $start_time = Time::Piece->strptime( "2-2-1993 $time1", "%d-%m-%Y %H:%M" );
    my $end_time;

    if ( $time1_hour < $time2_hour || ( $time1_hour == $time2_hour && $time1_minute < $time2_minute ) ) {
        $end_time = Time::Piece->strptime( "2-2-1993 $time2", "%d-%m-%Y %H:%M" );
    }
    else {
        $end_time = Time::Piece->strptime( "3-2-1993 $time2", "%d-%m-%Y %H:%M" );
    }

    while ( $start_time <= $end_time ) {

        #print $start_time->strftime('%H:%M') . "\n";
        ( $file_hour, $file_minute ) = split( /:/, $start_time->strftime('%H:%M') );

        #sys-snap not currently appending 0's to the front of files
        $file_minute =~ s/^0(\d)$/$1/;
        $file_hour =~ s/^0(\d)$/$1/;

        #print "$root_dir$snapshot_dir/$file_hour/$file_minute.log\n";
        push @snap_log_files, "$root_dir$snapshot_dir/$file_hour/$file_minute.log";
        $start_time += 60;
    }

    return @snap_log_files;
}

# since mem and cpu info gets printed to the same line, we already have the data at this point,
# and even sorting a large number of users by usage is relativly inexpensive, just going to mute unwanted output
sub run_basic {
    my $tmp          = shift;
    my $print_cpu    = shift;
    my $print_memory = shift;
    my %basic_usage;
    %basic_usage = %$tmp;

    my $sortby = 'cpu';
    if ( $print_cpu != 1 ) { $sortby = 'memory'; }
    foreach my $key (
        sort { $basic_usage{$b}->{$sortby} <=> $basic_usage{$a}->{$sortby} }
        keys %basic_usage
      ) {
        my $value = $basic_usage{$key};

        #printf( "user: %-15s\n\tcpu-score: %-12.2f \n\tmemory-score: %-12.2f\n\n", $key, $value->{cpu}, $value->{memory} );
        printf( "user: %-15s\n",             $key );
        printf( "\tcpu-score: %-12.2f\n",    $value->{cpu} ) if $print_cpu;
        printf( "\tmemory-score: %-12.2f\n", $value->{memory} ) if $print_memory;
    }
    print "\n";

    exit;
}

sub run_install {
    if ( not check_status ) {
        print "Start sys-snap logging to '/root/system-snapshot/' (y/n)?:";
        my $choice = "0";
        $choice = <STDIN>;
        while ( $choice !~ /[yn]/i ) {
            print "Start sys-snap logging to '/root/system-snapshot/' (y/n)?:";
            $choice = <STDIN>;
            chomp($choice);
        }
        if ( $choice =~ /[y]/i ) {
            print "Starting...\n";
        }
        else { print "Exiting...\n"; exit; }
    }
    else {
        print "Unable to start, only one sys-snap process should be active at a time\n";
        exit;
    }

    use File::Path qw(rmtree);
    use POSIX qw(setsid);

    ###############
    # Set Options #
    ###############

    # Set the time between snapshots in seconds
    my $sleep_time = 60;

    # The base directory under which to build the directory where snapshots are stored.
    my $root_dir = '/root';

    # Sometimes you won't have mysql and/or you won't have the root password to put in a .my.cnf file
    # if that's the case, set this to 0
    my $mysql = 1;

    # If the server has lighttpd or some other webserver, set this to 0
    # cPanel is autodetected later, so this setting is not used if running cPanel.
    my $apache = 1;

    # If you want extended data, set this to 1
    my $max_data = 0;

    # Get the date, hour, and min for various tasks
    my ( $sec, $min, $hour, $mday, $mon, $year, $wday, $yday, $isdst ) = localtime(time);
    $year += 1900;    # Format year correctly
    $mon++;           # Format month correctly
    $mon  = 0 . $mon  if $mon < 10;
    $mday = 0 . $mday if $mday < 10;
    my $date = $year . $mon . $mday;

    # Ensure target directory exists and is writable
    if ( !-d $root_dir ) {
        die "$root_dir is not a directory\n";
    }
    elsif ( !-w $root_dir ) {
        die "$root_dir is not writable\n";
    }

    if ( -d "$root_dir/system-snapshot" ) {
        system 'tar', 'czf', "${root_dir}/system-snapshot.${date}.${hour}${min}.tar.gz", "${root_dir}/system-snapshot";
        rmtree("$root_dir/system-snapshot");
    }

    if ( !-d "$root_dir/system-snapshot" ) {
        mkdir "$root_dir/system-snapshot";
    }

    # try to split process into background
    chdir '/' or die "Can't chdir to /: $!";
    open STDIN,  '/dev/null'  or die "Can't read /dev/null: $!";
    open STDOUT, '>/dev/null' or die "Can't write to /dev/null: $!";
    defined( my $pid = fork ) or die "Can't fork: $!";
    exit if $pid;
    print "$pid\n";
    setsid or die "Can't start a new session: $!";
    open STDERR, '>&STDOUT' or die "Can't dup stdout: $!";

    # Create a PID file for the new child process
    my $childpid = $$;
    my $pidfh;
    my $pidfile = $opt{'pidfile'};

    sysopen( $pidfh, $pidfile, O_RDWR | O_CREAT )
      or die "Could not open $pidfile: $!\n";
    print $pidfh "$childpid";
    flock( $pidfh, LOCK_NB | LOCK_EX )
      or die "Could not get lock on $pidfile: $!\n";

    ##########
    # Main() #
    ##########

    while (1) {

        # Ensure we have a current date/time
        ( $sec, $min, $hour, $mday, $mon, $year, $wday, $yday, $isdst ) = localtime(time);
        $year += 1900;    # Format year correctly
        $mon++;           # Format month correctly
        $mon  = 0 . $mon  if $mon < 10;
        $mday = 0 . $mday if $mday < 10;
        $date = $year . $mon . $mday;

        # go to the next log file
        mkdir "$root_dir/system-snapshot/$hour";
        my $current_interval = "$hour/$min";

        my $logfile = "$root_dir/system-snapshot/$current_interval.log";
        open( my $LOG, '>', $logfile )
          or die "Could not open log file $logfile, $!\n";

        # start actually logging #
        my $load = qx(cat /proc/loadavg);

        #print $LOG "Load Average:\n\n";  # without this line, you can get historical loads with head -n1 *
        print $LOG "$date $hour $min Load Average: $load\n";

        print $LOG "Memory Usage:\n\n";
        print $LOG qx(cat /proc/meminfo), "\n";

        print $LOG "Virtual Memory Stats:\n\n";
        print $LOG qx(vmstat 1 10), "\n";

        print $LOG "Process List:\n\n";
        print $LOG qx(ps awwxf -o user:20,pid,pcpu,pmem,vsz,rss,tty,stat,start,time,args), "\n";

        print $LOG "Network Connections:\n\n";
        print $LOG qx(netstat -anp), "\n";

        print $LOG "IO wait:\n\n";
        print $LOG qx(iostat), "\n";

        # optional logging
        if ($mysql) {
            print $LOG "MYSQL Processes:\n\n";
            print $LOG qx(mysqladmin proc), "\n";
        }

        print $LOG "Apache Processes:\n\n";
        if ( -f '/usr/local/cpanel/cpanel' ) {
            print $LOG qx(lynx --dump localhost/whm-server-status), "\n";
        }
        elsif ($apache) {
            print $LOG qx#lynx -width=1024 -dump http://localhost/server-status | egrep '(Client.+Request|GET|POST|HEAD)'#, "\n";
        }

        if ($max_data) {
            print $LOG "Process List for user Nobody:\n\n";
            my @process_list = qx(ps aux | grep [n]obody | awk '{print \$2}');
            foreach my $process (@process_list) {
                print $LOG qx(ls -al /proc/$process | grep cwd | grep home);
            }
            print $LOG "List of Open Files:\n\n";
            print $LOG qx(lsof), "\n";
        }

        close $LOG;

        # rotate the "current" pointer
        rmtree("$root_dir/system-snapshot/current");
        symlink "${current_interval}.log", "$root_dir/system-snapshot/current";

        sleep($sleep_time);
    }
}

sub module_sanity_check {
    eval("use Time::Piece;");
    if ($@) {
        print "WARNING: Perl Module Time::Piece.pm not installed!\n";
        print "Would you like sys-snap to attempt to install this moduel(y/n):";

        my $choice = <STDIN>;
        if ( $choice =~ /yes|y/i ) {
            print "Installing now - Please stand by.\n";
            system("cpan -i Time::Piece");
        }
        else {
            exit;
        }
    }
    return;
}