#!/opt/bin/perl
#
#########################################################################
#                                                                       #
#  Program to ensure periodically that only one copy of a program runs  #
#                                                                       #
#########################################################################
#                                                                       #
#   Version 1.0     -   Written 03.03.96 by Steffen Beyer               #
#                                                                       #
#########################################################################
#                                                                       #
#   Copyright (C) 1995 by software design & management GmbH & Co. KG    #
#                                                                       #
#########################################################################

# Configure here the name of the program to monitor:

# - absolute path and filename:

$program = '/opt/bin/prmonitor';

# - as a regular expression:

$pattern = '/opt/bin/prmonitor';

# Some defaults:

$version = 'version 1.0';

$self = $0;
$self =~ s!^.*/!!;

unless (open(PROCESSES, "ps -auxgw|"))
{
    die "$self: can't read from pipe 'ps -auxgw': $!\n";
}

while (<PROCESSES>)
{
    chop;
    ($user,$pid) = split(' ');
    $command = substr($_,56);
    if ($command =~ m!$pattern!o)
    {
        push(@PID, $pid);
    }
}

close(PROCESSES);

if (@PID > 1)
{
    foreach $pid (@PID)
    {
         system("/bin/kill -9 $pid");
         warn "$self: killed process $pid ($command)!\n";
    }
}

if (@PID != 1)
{
    system("/bin/nohup $program >/dev/null 2>$program.log &");
}

__END__