#!/usr/bin/env perl

# Program:     HP-UX-11iv3-ptree-kill.pl.txt
#
# Description: Cleanup of process tree on HP-UX servers
#
# If you obtain this script via Web, convert it to Unix format. For example:
# dos2ux HP-UX-ptree-kill.pl.txt > HP-UX-ptree-kill.pl
#
# Usage: HP-UX-ptree-kill.pl -h | -p PID
#
#        -h          Print help message
#        -p PID      Kill process tree that starts with PID
#
# Last Update: 21 April 2013
# Designed by: Dusan U. Baljevic (dusan.baljevic@ieee.org)
# Coded by:    Dusan U. Baljevic (dusan.baljevic@ieee.org)
#
# Copyright 2013-2015 Dusan Baljevic
# 
# 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, see <http://www.gnu.org/licenses/>.

# Define important environment variables
#
$ENV{'PATH'} = "/usr/bin:/usr/sbin:/sbin:/opt/perl/bin";

# Define Shell
#
$ENV{'SHELL'} = '/usr/bin/sh' if $ENV{'SHELL'} ne '';
$ENV{'IFS'}   = ''        if $ENV{'IFS'}   ne '';

# Enforce strictness
#
if ( eval "require strict" ) {
   import strict;
   use strict;
   no strict 'refs';
} else {
   print "WARN: Perl strict not found\n";
}

sub Usage {
    if ( eval "require File::Basename" ) {
        import File::Basename;
        $CMD = basename( "$0", ".pl" );
        Prusage();
    } else {
        $CMD = `basename $0`;
        chomp($CMD);
        Prusage();
    }
}

# Display usage if "-h" option is used
#
sub Prusage {
    print <<MYMSG
    USAGE: $CMD -h | -p PID
    -h          Print help message
    -p PID      Kill process tree that starts with PID
MYMSG
      ;
    exit(0);
}

# Ensure that modules are loaded
#
BEGIN {
   # Avoid zombies
   #
   # $SIG{CHLD} = 'IGNORE';

   $opts{p} = 0;

   if ( eval "require POSIX" ) {
      import POSIX 'uname';
      import POSIX qw(locale_h);
      use POSIX qw/getpgrp tcgetpgrp/;
      ( $System, $Hostname, $Maj, $Version, $Hardware ) = uname();
      if ( defined $Maj ) {
          ( $Major, $Minor, $Patch ) = split( /\./, $Maj );
      }
   }
   else {
      warn "WARN: Perl module POSIX not found\n";
   }

   use POSIX qw(:errno_h);

   if ( eval "require Getopt::Std" ) {
       import Getopt::Std;
       getopts( 'hp:', \%opts );
       if ( $opts{h} ) {
           &Usage;
       }

       $MYPPID  = $opts{p} || q{};
   } else {
       die "ERROR: Perl module Getopt::Std not found\n";
   }
}

# Define empty arrays
#
my @arr = ();
my @rev = ();

my $Maj      = q{};
my $Version  = q{};
my $Major    = q{};
my $Minor    = q{};
my $Patch    = q{};

if ( !"$Hostname" ) {
   my $VH = `uname -a 2>&1`;
   ( $System, $Hostname, $Maj, undef, $Hardware, undef ) =
     split( /\s+/, $VH );
   $Version = $Maj;
   ( $Major, $Minor, $Patch ) = split( /\./, $Maj );
}

if ( "$Minor$Patch" < 1131 ) {
   print "ERROR: This script should be run on HP-UX 11iv3 or higher\n";
   exit(1);
}

# Do not allow to run as unprivileged user
#
if ( $> != 0 ) {
   print "ERROR: This script should be run with root privileges\n";
   exit(1);
}

# Get the process tree from MYPPID
#
my @pstree = ();
if ( "$MYPPID" ) {
   @pstree = `ptree $MYPPID`;
} else {
   die "ERROR: PID not specified\n";
}

if ( ! "@pstree" ) {
   die "ERROR: No process tree found for PID $MYPPID\n";
   exit(1);
}

foreach my $i ( @pstree ) {
   # Get rid of whitespaces at the beginning of line
   #
   $i =~ s/^\s+//g;

   # The first column is the PID of the current line
   #
   ($mypid, undef) = split( /\s+/, $i );

   # Add the PID to the array in an orderly manner
   # to preserve the process hierarchy
   #
   push(@array, $mypid);
}

# Now, reverse the array elements
#
my @rev =  reverse(@array);

foreach my $proc (@rev) {
   # Check if the process is still alive
   # by sending it signal 0
   #
   if (kill 0 => $proc) {
      print "INFO: Process $proc is alive... Attempting to kill it\n";
      # Now, try to kill the process
      #
     print "kill(\"TERM\", $proc)\n";
#      kill("TERM", $proc);
   } elsif ($! == EPERM) {             # changed uid
      print "WARNING: Process $proc has escaped the control\n";
   } elsif ($! == ESRCH) {
      print "WARNING: Process $proc is deceased\n";    # or zombied
   } else {
      warn "WARNING: Could not check the status of process $proc: $!\n";
   }
}

# Clean exit
#
exit(0);