Class: MindControl::Server

Inherits:
Object
  • Object
show all
Includes:
Loggable
Defined in:
lib/mind_control/server.rb

Overview

Listens UNIX socket and starts REPL sessions.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(socket_path, repl) ⇒ Server

Returns a new instance of Server.

Parameters:

  • socket_path (String) —

    Absolute path of UNIX socket.

  • repl (#start) —

    Instance of REPL (@see MindControl::REPL).



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# File 'lib/mind_control/server.rb', line 23

def initialize( socket_path, repl )
  @socket_path, @repl = socket_path, repl
end

Instance Attribute Details

#repl ⇒ Object (readonly)

Returns the value of attribute repl.



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# File 'lib/mind_control/server.rb', line 17

def repl
  @repl
end

#socket_path ⇒ Object (readonly)

Returns the value of attribute socket_path.



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# File 'lib/mind_control/server.rb', line 16

def socket_path
  @socket_path
end

Instance Method Details

#get_client_id(socket) ⇒ String

Return id string for connected client.

Parameters:

  • socket (UNIXSocket) —

    Client socket.

Returns:

  • (String) 


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# File 'lib/mind_control/server.rb', line 111

def get_client_id( socket )
  # UNIX socket return effective UID/GID for connected client
  euid, _ = socket.getpeereid

  # Find record in /etc/passwd
   = Etc.getpwuid euid

  return "#{.name} (#{.gecos})"
end

#handle_client_connection(socket, client_id) ⇒ Object

Starts REPL session in separate thread for connected client.

Parameters:

  • socket (Socket) —

    Client socket.

  • client_id (String) —

    ID string for connected client.



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# File 'lib/mind_control/server.rb', line 127

def handle_client_connection( socket, client_id )
  info "Starting new MindControl session for user #{client_id} ..."

  # Client will send us his STDIN and STDOUT
  client_stdin, client_stdout = socket.recv_io, socket.recv_io

  # Start REPL
  repl.start client_stdin, client_stdout

  info "MindControl session for user #{client_id} has ended!"
rescue Exception => e
  error_message = "REPL exception: #{e.message} (#{e.class.name})\n#{e.backtrace.join( "\n" )}"
  error error_message

  # Send error to client
  client_stdout.puts error_message if client_stdout
end

#running? ⇒ Boolean

Server is running?

Returns:

  • (Boolean) 


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# File 'lib/mind_control/server.rb', line 79

def running?
  @server_thread && @server_thread.alive?
end

#start ⇒ Object

Start server.



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# File 'lib/mind_control/server.rb', line 30

def start
  return if running?

  info "Starting MindControl server on #{socket_path} ..."

  # Storage for client threads
  client_threads = ThreadGroup.new

  # Start acceptor thread
  @server_thread = Thread.new do
    begin
      start_server_loop( socket_path ) do |client_socket|
        # Process client in new thread
        client_threads.add Thread.new {
          begin
            handle_client_connection( client_socket, get_client_id( client_socket ))
          ensure
            # We MUST close the socket
            client_socket.close
          end
        }
      end
    ensure
      # Kill all client threads on server stop
      client_threads.list.each( &:kill )
    end
  end

  # We should known if our server has failed
  @server_thread.abort_on_exception = true
end

#start_server_loop(socket_path, &block) ⇒ Object

Starts UNIX server, accepts clients and yields its sockets in loop.

Parameters:

  • socket_path (String) —

    Path to UNIX socket to bind to.



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# File 'lib/mind_control/server.rb', line 89

def start_server_loop( socket_path, &block )
  # Remove old file
  FileUtils.rm_f socket_path
  FileUtils.mkdir_p File.dirname( socket_path )

  UNIXServer.open( socket_path ) do |server|
    loop do
      # Wait for client
      block.call server.accept
    end
  end
ensure
  # Cleanup
  FileUtils.rm socket_path
end

#stop ⇒ Object

Stop server.



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# File 'lib/mind_control/server.rb', line 65

def stop
  return unless running?

  info "Stopping MindControl server ..."

  # Kill acceptor thread
  @server_thread.kill
  @server_thread.join
  @server_thread = nil
end