#! /usr/bin/perl
#
use Getopt::Long;
use Sys::Syslog;

$opt_u=99;
$opt_a=0;
$opt_k=0;
$opt_n=0;
$opt_s=0;
&GetOptions(qw(u:i a n s k|kill=i));

my $MOMCTL = '/usr/sbin/momctl';
my $PBSMOM = '/usr/sbin/pbs_mom';

@lines=`ps -efl`;
$opt_a and do {
  open MOMCTL,"$MOMCTL -h localhost -d 0 |" or die "Cannot run momctl: $!\n";
  while(<MOMCTL>) { 
    chomp; 
    /sidlist=/  and do { split(/=/); push @ARGV,$_[$#_]; };
  }
  close MOMCTL;
};

foreach ( @lines ) {
  ! /\d+/ && next;      # remove header from ps -efl, which contains no number (PID!)
  chomp; split(/\s+/,$_,15);
  $opt_n and ($_[12] =~ /(tty|pts)/) and next;
  ( $_[14] eq "$PBSMOM" ) and $mompid=$_[3];
  $children{$_[4]}.=" $_[3]";
  $name{$_[3]} = $_[14];
  $owner{$_[3]} = (getpwnam($_[2]))[2];
}

@ARGV[0] or push @ARGV,$mompid;

sub prunebranch($) {
  my ($pid) = @_;
  foreach ( split(/\s+/,$children{$pid}) ) {
    ($_ =~ /\d+/ ) and &prunebranch($_);
  }
  $name{$pid}=undef if $owner{$pid};
  return;
}

sub removebranch($) {
  my ($pid) = @_;
  foreach ( split /\s+/, $children{$pid} ) {
    ($_ ne "") and &removebranch($_);
  }
  $children{$pid} = undef;
  $owner{$pid} = undef;
  $name{$pid} = undef;
}

foreach ( @ARGV ) { &prunebranch($_); }


foreach ( keys %name ) {
  # Do not kill $PBSMOM
  if ($name{$_} =~ m!^\s*$PBSMOM\s*!) {
    &removebranch($_);
  }

  # option -s also forces removal of branches starting at an sshd
  if (! $opt_s and $name{$_} =~ /sshd: \w+\@pts/) {
    &removebranch($_);
  }
}

openlog("prune_userprocs", 'pid', 'user') or
    warn "Sys::Sylog:openlog failed\n";
    
foreach ( keys %name ) {
  ($owner{$_} > $opt_u) and $name{$_} and do {
    syslog('notice', "killing pid=%d uid=%s cmd=%s\n", $_, $owner{$_}, $name{$_});
    if($opt_k) { kill $opt_k,$_; }
  };
}

closelog();