From: cacciatc <Chris.Killimanjaro@...>
Date: 2007-11-21T13:35:00+09:00
Subject: problems with TCPSocket

I am trying out a little code for a client/server and I was testing to
see how many simultaneous clients the server
could handle, but I always get a "Bad file descriptor - connect(2)"
error message, exactly after the sixth client connects.  I have tried
it with my firewall disabled and I'm testing it on laptop that runs
Win XP.  Any help would be much appreciated.

cacciatc

Here are my client and server:

class Client
  def initialize(addr,p)
    begin
      @t = TCPSocket.new(addr,p)
      print "connecting to " + addr.to_s + " on port " + p.to_s +
"..."
    rescue
      puts "error: #{$!}"
    else
      puts "connected"
    end
  end #end init

  def safe_gets
    begin
      output = @t.gets
    rescue
      puts "error: #{$!}"
      tear_down
    else
      return output
    end
  end #end safe gets

  def safe_write(sock,msg)
    begin
      sock.write(msg)
    rescue
      @desc.delete(sock)
      sock.close
    end
  end

  def get_login
    out1 = safe_gets
    out2 = safe_gets
    print out1.chomp
    @name = gets
    print out2.chomp
    @passwd = gets
  end #end get login

  def connect
    safe_write(@t,@name.chomp + " " + @passwd)
    out = safe_gets
    out
  end #end connect

  def run
    get_login
    if connect != "Welcome\n" then
      puts "incorrect name or passwd"
      get_login
      if connect != "Welcome\n" then
        tear_down
      end
    end
    #processing loop
    while 1
     # puts @t.gets
      print ">> "
      input = gets
      safe_write(@t,input)
      if input.downcase == "q\n" then
        tear_down
      end
      out = safe_gets
      puts out
    end
    tear_down
  end #end run

  def tear_down
    @t.close
    exit
  end # end tear down

end #end Client

c = Array.new(25)
cnt = 0
while cnt < 25
  c.push(Client.new("localhost",10001))
  i = 0
  while i < 1000000
    i+=1
  end
  cnt += 1
end
c.each {|cl| cl.run}
c.each {|cl| cl.tear_down}


class Logind
  def initialize(p)
    @t = TCPServer.new(p)
    @t.setsockopt(Socket::SOL_SOCKET, Socket::SO_REUSEADDR,1)
    @desc  = Array.new
    @gdesc = Hash.new
    @desc.push(@t)
  end

  def accept_new_connection
    begin
      newsock = @t.accept
    rescue Errno::EAGAIN, Errno::ECONNABORTED, Errno::EINTR
      IO.select[@t]
      retry
    end
    newsock.write("username: \npasswd: \n")
    begin
      input = safe_gets(newsock)
    rescue
      #log bad socket
      puts newsock
      newsock.close
    else
      safe_write(newsock,"Welcome\n")
      @desc.push(newsock)
    end
  end #end accept_new_connection

  def run
    while true
      res = select(@desc,nil,nil,nil)
      if res != nil then
        for sock in res[0]
          if sock == @t then
            accept_new_connection
          else
            if sock.eof? then
              sock.close
              @desc.delete(sock)
            else
              input = safe_gets(sock)
            end
          end
        end #end for
      end #end select test
    end #end while
  end # end run

  def safe_gets(sock)
    ret_cnt = 0
    begin
      out = sock.gets
    rescue
      if ret_cnt < 5 then
        ret_cnt+=1
        retry
      end
    else
      return out
    end
  end

  def safe_write(sock,msg)
    ret_cnt = 0
    begin
      sock.write(msg)
    rescue
       if ret_cnt < 5 then
        ret_cnt+=1
        retry
      end
    end
  end

end #end logind

l = Logind.new(10001)
l.run