#!/usr/bin/perl
#
# Use try to connect to a http server.
# For use with "mon".
#
# Arguments are "-p port host [host...]"
#
# Jon Meek
# American Cyanamid Company
# Princeton, NJ
#
# $Id: http.monitor,v 1.4 1998/04/29 14:29:41 trockij Exp $
#
#    Copyright (C) 1998, Jim Trocki
#
#    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 2 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
use Getopt::Std;
use English;

getopts ("p:t:u:");
$PORT = $opt_p || 80;
$TIMEOUT = $opt_t || 30;
$URL = $opt_u || "/";

@failures = ();

foreach $host (@ARGV) {

    $OK = &httpGET($host, $PORT);

    if (!defined (OK) || $OK == 0) {
	push (@failures, $host);
    }
}

if (@failures == 0) {
    exit 0;
}

print "@failures\n";

exit 1;


sub httpGET {
    use Socket;
    use Sys::Hostname;

    my($Server, $Port) = @_;
    my($ServerOK, $TheContent);

    $TheContent = '';

    $Path = $URL;

###############################################################
    eval {

	local $SIG{ALRM} = sub { die "Timeout Alarm" };
	alarm $TIMEOUT;
	$result = &OpenSocket($Server, $Port); # Open a connection to the server
	if ($result == 0) { # Failure to open the socket
	    return '';
	}

	print S "GET $Path HTTP/1.0\r\n";
	print S "User-Agent: mon.d/http.monitor\r\n\r\n";

	while ($in = <S>) {
	    $TheContent .= $in;  # Store data for later processing
	}

# HTTP/1.1 200 OK

	if ($TheContent =~ /^HTTP\/([\d\.]+)\s+200\b/) {
	    $ServerOK = 1;
	} else {
	    $ServerOK = 0;
	}

	close(S);
	alarm 0; # Cancel the alarm

    };

    if ($EVAL_ERROR and ($EVAL_ERROR eq 'Timeout Alarm')) {
	print "**** Time Out\n";
	return 0;
    }
    return $ServerOK;

}

sub OpenSocket {
#
# Make a Berkeley socket connection between this program and a TCP port
#  on another (or this) host. Port can be a number or a named service
#
    local($OtherHostname, $Port) = @_;
    local($OurHostname, $sockaddr, $name, $aliases, $proto, $type, $len,
	  $ThisAddr, $this, $that);
    $OurHostname = &hostname;

    ($name, $aliases, $proto) = getprotobyname('tcp');
    ($name, $aliases, $Port) = getservbyname($Port, 'tcp') unless $Port =~ /^\d+$/;
    ($name, $aliases, $type, $len, $ThisAddr) = gethostbyname($OurHostname);
    ($name, $aliases, $type, $len, $OtherHostAddr) = gethostbyname($OtherHostname);

    $sockaddr = 'S n a4 x8';    # Format for packed network address
    $this = pack($sockaddr, &AF_INET, 0, $ThisAddr);
    $that = pack($sockaddr, &AF_INET, $Port, $OtherHostAddr);

    $result = socket(S, &PF_INET, &SOCK_STREAM, $proto) || return undef;

    $result = bind(S, $this) || return undef;

    $result = connect(S, $that) || return undef;

    select(S); $| = 1; select(STDOUT);      # set S to be un-buffered
    return 1;                               # success
}
