create sockets with SO_REUSEPORT option

lib/ruby-debug-ide.rb

@@ -18,11 +18,8 @@
 module Debugger
 
   class << self
-    def find_free_port(host)
-      server = TCPServer.open(host, 0)
-      port   = server.addr[1]
-      server.close
-      port
+    def is_windows
+      RbConfig::CONFIG['host_os'] =~ /mswin|msys|mingw|cygwin|bccwin|wince|emc/
     end
 
     # Prints to the stderr using printf(*args) if debug logging flag (-d) is on.
@@ -122,18 +119,22 @@ def start_control(host, port, notify_dispatcher)
 
           server = notify_dispatcher_if_needed(host, port, notify_dispatcher) do |real_port, port_changed|
             s = TCPServer.new(host, real_port)
+            s.setsockopt(:SOCKET, :REUSEADDR, 2)
             print_greeting_msg $stderr, host, real_port, port_changed ? "Subprocess" : "Fast" if defined? IDE_VERSION
+            puts "#{s.getsockopt(:SOCKET, :REUSEADDR).bool}"
             s
           end
 
           return unless server
 
           while (session = server.accept)
+            server.close
             $stderr.puts "Connected from #{session.peeraddr[2]}" if Debugger.cli_debug
             dispatcher = ENV['IDE_PROCESS_DISPATCHER']
             if dispatcher
               ENV['IDE_PROCESS_DISPATCHER'] = "#{session.peeraddr[2]}:#{dispatcher}" unless dispatcher.include?(":")
               ENV['DEBUGGER_HOST'] = host
+              ENV['DEBUGGER_PORT'] = port.to_s
             end
             begin
               @interface = RemoteInterface.new(session)
@@ -165,13 +166,10 @@ def notify_dispatcher_if_needed(host, port, need_notify)
 
       3.times do |i|
         begin
+          $stderr.puts "#{Process.pid}: go create dispatcher socket #{acceptor_host} #{acceptor_port}"
           s = TCPSocket.open(acceptor_host, acceptor_port)
           dispatcher_answer = s.gets.chomp
 
-          if dispatcher_answer == "true"
-            port = Debugger.find_free_port(host)
-          end
-
           server = yield port, dispatcher_answer == "true"
 
           s.print(port)
@@ -186,6 +184,8 @@ def notify_dispatcher_if_needed(host, port, need_notify)
           sleep 0.3
         end unless connected
       end
+
+      nil
     end
   end
 

lib/ruby-debug-ide/command.rb

@@ -173,7 +173,7 @@ def realpath(filename)
       if filename.index(File::SEPARATOR) || File::ALT_SEPARATOR && filename.index(File::ALT_SEPARATOR)
         filename = File.expand_path(filename)
       end
-      if (RUBY_VERSION < '1.9') || (RbConfig::CONFIG['host_os'] =~ /mswin/)
+      if (RUBY_VERSION < '1.9') || Debugger.is_windows
         filename
       else
         filename = File.realpath(filename) rescue filename

lib/ruby-debug-ide/multiprocess/pre_child.rb

@@ -5,13 +5,11 @@ def pre_child(options = nil)
         require 'socket'
         require 'ostruct'
 
-        host = ENV['DEBUGGER_HOST']
-
         options ||= OpenStruct.new(
             'frame_bind'  => false,
-            'host'        => host,
+            'host'        => ENV['DEBUGGER_HOST'],
             'load_mode'   => false,
-            'port'        => Debugger.find_free_port(host),
+            'port'        => ENV['DEBUGGER_PORT'],
             'stop'        => false,
             'tracing'     => false,
             'int_handler' => true,
@@ -23,8 +21,7 @@ def pre_child(options = nil)
             'inspect_time_limit' => 100
         )
 
-        if(options.ignore_port)
-          options.port = Debugger.find_free_port(options.host)
+        if options.ignore_port
           options.notify_dispatcher = true
         end