#!/usr/bin/env perl

# Copyright (c) 2009, Douglas Haber
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above 
#       copyright notice, this list of conditions and the following
#       disclaimer in the documentation and/or other materials provided
#       with the distribution.
#     * The names names of the authors may not be used to endorse or
#       promote products derived from this software without specific
#       prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND ITS
# CONTRIBUTERS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR ITS
# CONTRIBUTERS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.

#killgrep
#  Send signal to all process that match a regular expression.
#  (Similar to pkill, but with less flexibility and better output.)

# WARNING:  This is very hackish and was writen when it was needed for
#           a particular situation.  There almost definitely is a 
#           better and safer way to get things done than using this script.
#           Be very careful if running as root or using regexs that 
#           match too many processes.

$REGEX = "";
$SIGNAL = "";
$0 = "killgrep";

sub display_help {
    print "USAGE:\n";
    print "   killgrep [signal] [regex]\n";
    print "     *  if signal is 0 no signal is sent and \n";
    print "        all matching processes are listed.\n";
    print "     *  if signal is not provided 2 is  assumed\n";
    exit(1);
}

sub valid_regex {
    # Check the validity of a regular expression
    eval {
	"" =~ /$_[0]/; 
        return(1);    
    } or return(0);
}

sub main {
    if($#ARGV==-1 || $#ARGV>1) { display_help(); }
    
    $REGEX = pop(@ARGV);
    if($#ARGV == -1) { $SIGNAL = 2; }
    else             { $SIGNAL = int(pop(@ARGV)); }
   
    if(!valid_regex($REGEX)) {
	die "ERROR:  Regular expression '$REGEX' is not valid.\n"; 
    }

    foreach $line (split(/\n/, `ps awwx -o pid,cmd`)) {
        my ($pid, $cmd) = $line =~ /^\s*(\d+) (.*)$/;

        if($cmd =~ /$REGEX/) {
            printf("%-14.14s  %s", "kill -$SIGNAL $pid", "# $cmd\n");
            if($pid != $$ && $SIGNAL != 0) { 
		kill($SIGNAL, $pid);
	    }
        }
    }
}

main();