improve attach mode to affect child processes (#108)

This commit enables the attachment to the child processes of the original one.
Useful for debugging application servers (see https://youtrack.jetbrains.com/issue/RUBY-19369)

Author: viuginick1

bin/gdb_wrapper

@@ -1,6 +1,7 @@
 #!/usr/bin/env ruby
 
 require 'optparse'
+require 'thread'
 require 'ostruct'
 
 $stdout.sync = true
@@ -65,6 +66,7 @@ unless options.ruby_path
 end
 
 argv = '["' + ARGV * '", "' + '"]'
+child_argv = '["' + ARGV * '", "' + "', '--ignore-port" + '"]'
 debugger_loader_path = File.expand_path(File.dirname(__FILE__)) + '/../lib/ruby-debug-ide/attach/debugger_loader'
 
 options.gems_to_include.each do |gem_path|
@@ -78,51 +80,17 @@ require 'ruby-debug-ide/attach/util'
 require 'ruby-debug-ide/attach/native_debugger'
 require 'ruby-debug-ide/attach/process_thread'
 
-debugger = choose_debugger(options.ruby_path, options.pid, options.gems_to_include, debugger_loader_path, argv)
 
-trap('INT') do
-  unless debugger.exited?
-    $stderr.puts "backtraces for threads:\n\n"
-    process_threads = debugger.process_threads
-    if process_threads
-      process_threads.each do |thread|
-        $stderr.puts "#{thread.thread_info}\n#{thread.last_bt}\n\n"
-      end
-    end
-    debugger.exit
-  end
-  exit!
-end
+child_pids = get_child_pids(options.pid.to_s)
+attach_threads = Array.new
+attach_threads << attach_and_return_thread(options, options.pid, debugger_loader_path, argv)
 
-debugger.attach_to_process
-debugger.set_flags
+attach_threads << child_pids.map {|pid| attach_and_return_thread(options, pid, debugger_loader_path, child_argv)}
 
+
+attach_threads.each {|thread| thread.join}
 if options.uid
   DebugPrinter.print_debug("changing current uid from #{Process.uid} to #{options.uid}")
   Process::Sys.setuid(options.uid.to_i)
 end
-
-if debugger.check_already_under_debug
-  $stderr.puts "Process #{debugger.pid} is already under debug"
-  debugger.exit
-  exit!
-end
-
-should_check_threads_state = true
-
-while should_check_threads_state
-  should_check_threads_state = false
-  debugger.update_threads.each do |thread|
-    thread.switch
-    while thread.need_finish_frame
-      should_check_threads_state = true
-      thread.finish
-    end
-  end
-end
-
-debugger.wait_line_event
-debugger.load_debugger
-debugger.exit
-
 sleep

bin/rdebug-ide

@@ -48,7 +48,7 @@ EOB
   end
 
   opts.on("-h", "--host HOST", "Host name used for remote debugging") {|host| options.host = host}
-  opts.on("-p", "--port PORT", Integer, "Port used for remote debugging") {|port| options.port = port}  
+  opts.on("-p", "--port PORT", Integer, "Port used for remote debugging") {|port| options.port = port}
   opts.on("--dispatcher-port PORT", Integer, "Port used for multi-process debugging dispatcher") do |dp| 
     options.dispatcher_port = dp
   end
@@ -71,6 +71,9 @@ EOB
   opts.on("--attach-mode", "Tells that rdebug-ide is working in attach mode") do
     options.attach_mode = true
   end
+  opts.on("--ignore-port", "Generate another port") do
+    options.ignore_port = true
+  end
   opts.on("--keep-frame-binding", "Keep frame bindings") {options.frame_bind = true}
   opts.on("--disable-int-handler", "Disables interrupt signal handler") {options.int_handler = false}
   opts.on("--rubymine-protocol-extensions", "Enable all RubyMine-specific incompatible protocol extensions") do

lib/ruby-debug-ide/attach/util.rb

@@ -1,5 +1,76 @@
 require 'ruby-debug-ide/attach/lldb'
 require 'ruby-debug-ide/attach/gdb'
+require 'socket'
+
+def attach_and_return_thread(options, pid, debugger_loader_path, argv)
+  Thread.new(argv) do |argv|
+
+    debugger = choose_debugger(options.ruby_path, pid, options.gems_to_include, debugger_loader_path, argv)
+
+    trap('INT') do
+      unless debugger.exited?
+        $stderr.puts "backtraces for threads:\n\n"
+        process_threads = debugger.process_threads
+        if process_threads
+          process_threads.each do |thread|
+            $stderr.puts "#{thread.thread_info}\n#{thread.last_bt}\n\n"
+          end
+        end
+        debugger.exit
+      end
+      exit!
+    end
+
+    debugger.attach_to_process
+    debugger.set_flags
+
+    if debugger.check_already_under_debug
+      $stderr.puts "Process #{debugger.pid} is already under debug"
+      debugger.exit
+      exit!
+    end
+
+    should_check_threads_state = true
+
+    while should_check_threads_state
+      should_check_threads_state = false
+      debugger.update_threads.each do |thread|
+        thread.switch
+        while thread.need_finish_frame
+          should_check_threads_state = true
+          thread.finish
+        end
+      end
+    end
+
+    debugger.wait_line_event
+    debugger.load_debugger
+    debugger.exit
+  end
+end
+
+def get_child_pids(pid)
+  return [] unless command_exists 'pgrep'
+
+  pids = Array.new
+
+  q = Queue.new
+  q.push(pid)
+
+  while (!q.empty?) do
+    pid = q.pop
+
+    pipe = IO.popen("pgrep -P #{pid}")
+
+    pipe.readlines.each do |child|
+      child_pid = child.strip.to_i
+      q.push(child_pid)
+      pids << child_pid
+    end
+  end
+
+  pids
+end
 
 def command_exists(command)
   checking_command = "checking command #{command} for existence\n"

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

@@ -19,6 +19,11 @@ def pre_child(options = nil)
             'notify_dispatcher' => true
         )
 
+        if(options.ignore_port)
+          options.port = find_free_port(options.host)
+          options.notify_dispatcher = true
+        end
+      
         start_debugger(options)
       end
 
@@ -39,7 +44,6 @@ def start_debugger(options)
         Debugger.keep_frame_binding = options.frame_bind
         Debugger.tracing = options.tracing
         Debugger.cli_debug = options.cli_debug
-
         Debugger.prepare_debugger(options)
       end