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Diffstat (limited to 'lib/ping.rb')
-rw-r--r-- | lib/ping.rb | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/lib/ping.rb b/lib/ping.rb new file mode 100644 index 0000000000..d742a50f99 --- /dev/null +++ b/lib/ping.rb @@ -0,0 +1,55 @@ +# +# ping.rb -- check a host for upness +# +#= SYNOPSIS +# +# require 'ping' +# print "'jimmy' is alive and kicking\n" 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 (I<not> an ICMP one) 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) onto. +# +#== Parameters +# +# : hostname +# +# The remote host to check, specified either as a hostname or as an +# IP address. +# +# : timeout +# +# The timeout in seconds. If not specified it will default to 5 seconds. +# +#= WARNING +# +# pingecho() uses user-level thread to implement the timeout, so it may block +# for long period if named does not respond for some reason. +# +#=end + +module Ping + require "socket" + def pingecho(host, timeout=5) + begin + x = Thread.current + y = Thread.start { + sleep timeout + x.raise RuntimeError if x.status + } + s = TCPsocket.new(host, "echo") + s.close + return TRUE + rescue + return FALSE; + ensure + Thread.kill y if y.status + end + end + module_function "pingecho" +end |