Threading methods & args

ruby-talk
1

Well, this is my simple port scanner
Instead of actually Threading the scan it just prints:
"C:\Users\admin>C:\Ruby193\bin\ruby.exe
C:\Users\admin\Desktop\port-scanner.rb
choose host:"
why ?

require 'socket'

def scanner
  print "choose host: "
  arg1 = gets.chomp
  print "choose starting port: "
  arg2 = gets.to_i
  print "choose ending port: "
  arg3 = gets.to_i
  while arg2 <= arg3
    begin
      s = TCPSocket.new(arg1, arg2) # arg1 = host, arg2 = sport, arg3 =
eport
      if s
        puts "Port #{arg2} is open!"
      end
    rescue
      puts "Port #{arg2} is closed!"
    end
    arg2 += 1

  end
end

Thread.start {scanner}

···

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2

*) You only launch one thread
*) You launch your whole program in that one thread
*) Your main thread doesn't wait for the thread to do its work
*) You probably want to use Thread#new rather than Thread#start

This is not at all good, but works along the lines of what you are doing here. Obviously there is a LOT of code missing.

···

On 08/27/2012 10:05 AM, bar hofesh wrote:

Well, this is my simple port scanner
Instead of actually Threading the scan it just prints:
"C:\Users\admin>C:\Ruby193\bin\ruby.exe
C:\Users\admin\Desktop\port-scanner.rb
choose host:"
  why ?

require 'socket'

def scanner
   print "choose host: "
   arg1 = gets.chomp
   print "choose starting port: "
   arg2 = gets.to_i
   print "choose ending port: "
   arg3 = gets.to_i
   while arg2 <= arg3
     begin
       s = TCPSocket.new(arg1, arg2) # arg1 = host, arg2 = sport, arg3 =
eport
       if s
         puts "Port #{arg2} is open!"
       end
     rescue
       puts "Port #{arg2} is closed!"
     end
     arg2 += 1

   end
end

Thread.start {scanner}

#===============================================================================
#!/usr/bin/env ruby

require 'socket'
require 'logger'

def scanner
   log = Logger.new(STDOUT)
   print "choose host: "
   host = gets.chomp
   print "choose starting port: "
   start_port = gets.to_i
   print "choose ending port: "
   end_port = gets.to_i
   puts "Scanning #{host} from #{start_port} to #{end_port}"
   threads =
   (start_port..end_port).each {|port|
     threads << Thread.new {
       begin
         s = TCPSocket.new(host, port)
         if s
           log.info { "Port #{port} is open!" }
         end
       rescue
         log.info { "Port #{port} is closed!" }
       ensure
         s.close if s
       end
     }
   }
   threads.each { |thread| thread.join }
end

scanner

#===============================================================================

Hope that helps/ gets you started =]

Sam

3

Hi,

This makes no sense. What you're doing is create a single thread at the
end of the code. How is this thread supposed to create any concurrency?
It probably won't even run, because the main thread will exit at pretty
much the same time.

What you probably want to do is create the socket objects in separate
threads. So do it:

Thread.new do
  s = TCPSocket.new ...
  ...
end

But you must save the thread objects in an array and call "join" for
each of them in the main thread. This will make the main thread wait for
the socket threads to finish.

···

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