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#
# ping.rb -- check a host for upness
#
require 'timeout'
require "socket"
#= SYNOPSIS
#
# require 'ping'
#
# puts "'jimmy' is alive and kicking" if Ping.pingecho('jimmy', 10)
#
#= DESCRIPTION
#
# This module contains routines to test for the reachability of remote hosts.
# Currently the only routine implemented is pingecho().
#
# pingecho() uses a TCP echo (_not_ an ICMP echo) to determine if the
# remote host is reachable. This is usually adequate to tell that a remote
# host is available to rsh(1), ftp(1), or telnet(1) to.
#
#= WARNING
#
# pingecho() may block for a long period if name resolution is slow. Require
# 'resolv-replace' to use non-blocking name resolution.
#
module Ping
# return true if we can open a connection to the hostname or IP address
# +host+ on port +service+ (which defaults to the "echo" port) waiting up to
# +timeout+ seconds.
def pingecho(host, timeout=5, service="echo")
begin
timeout(timeout) do
s = TCPSocket.new(host, service)
s.close
end
rescue Errno::ECONNREFUSED
return true
rescue Timeout::Error, StandardError
return false
end
return true
end
module_function :pingecho
end
if $0 == __FILE__
host = ARGV[0]
host ||= "localhost"
printf("%s alive? - %s\n", host, Ping::pingecho(host, 5))
end
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