More robust shutdown sequence with warning on unclean shutdown.

src/frontend/stmclient.cc

@@ -87,6 +87,10 @@ void STMClient::init( void )
   if ( !getenv( "MOSH_TITLE_NOPREFIX" ) ) {
     overlays.set_title_prefix( wstring( L"[mosh] " ) );
   }
+
+  wchar_t tmp[ 128 ];
+  swprintf( tmp, 128, L"Nothing received from server on UDP port %d.", port );
+  connecting_notification = wstring( tmp );
 }
 
 void STMClient::shutdown( void )
@@ -109,6 +113,10 @@ void STMClient::shutdown( void )
     fprintf( stderr, "mosh did not make a successful connection to %s:%d.\n", ip.c_str(), port );
     fprintf( stderr, "Please verify that UDP port %d is not firewalled and can reach the server.\n\n", port );
     fprintf( stderr, "(By default, mosh uses a UDP port between 60000 and 61000. The -p option\nselects a specific UDP port number.)\n" );
+  } else if ( network ) {
+    if ( !clean_shutdown ) {
+      fprintf( stderr, "\n\nmosh did not shut down cleanly. Please note that the\nmosh-server process may still be running on the server.\n" );
+    }
   }
 }
 
@@ -223,7 +231,7 @@ bool STMClient::process_user_input( int fd )
       if ( quit_sequence_started ) {
 	if ( the_byte == '.' ) { /* Quit sequence is Ctrl-^ . */
 	  if ( network->has_remote_addr() && (!network->shutdown_in_progress()) ) {
-	    overlays.get_notification_engine().set_notification_string( wstring( L"Exiting on user request..." ) );
+	    overlays.get_notification_engine().set_notification_string( wstring( L"Exiting on user request..." ), true );
 	    network->start_shutdown();
 	    return true;
 	  } else {
@@ -328,7 +336,7 @@ void STMClient::main( void )
 	  if ( !network->has_remote_addr() ) {
 	    break;
 	  } else if ( !network->shutdown_in_progress() ) {
-	    overlays.get_notification_engine().set_notification_string( wstring( L"Exiting..." ) );
+	    overlays.get_notification_engine().set_notification_string( wstring( L"Exiting..." ), true );
 	    network->start_shutdown();
 	  }
 	}
@@ -346,7 +354,7 @@ void STMClient::main( void )
 	  if ( !network->has_remote_addr() ) {
 	    break;
 	  } else if ( !network->shutdown_in_progress() ) {
-	    overlays.get_notification_engine().set_notification_string( wstring( L"Signal received, shutting down..." ) );
+	    overlays.get_notification_engine().set_notification_string( wstring( L"Signal received, shutting down..." ), true );
 	    network->start_shutdown();
 	  }
 	}
@@ -364,13 +372,14 @@ void STMClient::main( void )
 	if ( !network->has_remote_addr() ) {
 	  break;
 	} else if ( !network->shutdown_in_progress() ) {
-	  overlays.get_notification_engine().set_notification_string( wstring( L"Exiting..." ) );
+	  overlays.get_notification_engine().set_notification_string( wstring( L"Exiting..." ), true );
 	  network->start_shutdown();
 	}
       }
 
       /* quit if our shutdown has been acknowledged */
       if ( network->shutdown_in_progress() && network->shutdown_acknowledged() ) {
+	clean_shutdown = true;
 	break;
       }
 
@@ -381,14 +390,11 @@ void STMClient::main( void )
 
       /* quit if we received and acknowledged a shutdown request */
       if ( network->counterparty_shutdown_ack_sent() ) {
+	clean_shutdown = true;
 	break;
       }
 
       /* write diagnostic message if can't reach server */
-      wchar_t tmp[ 128 ];
-      swprintf( tmp, 128, L"Nothing received from server on UDP port %d.", port );
-      wstring connecting_notification( tmp );
-
       if ( still_connecting()
 	   && (!network->shutdown_in_progress())
 	   && (timestamp() - network->get_latest_remote_state().timestamp > 250) ) {

src/frontend/stmclient.h

@@ -44,7 +44,9 @@ private:
   Network::Transport< Network::UserStream, Terminal::Complete > *network;
   Terminal::Display display;
 
+  std::wstring connecting_notification;
   bool repaint_requested, quit_sequence_started;
+  bool clean_shutdown;
 
   void main_init( void );
   bool process_network_input( void );
@@ -70,8 +72,10 @@ public:
       overlays(),
       network( NULL ),
       display( true ), /* use TERM environment var to initialize display */
+      connecting_notification(),
       repaint_requested( false ),
-      quit_sequence_started( false )
+      quit_sequence_started( false ),
+      clean_shutdown( false )
   {
     if ( predict_mode ) {
       if ( !strcmp( predict_mode, "always" ) ) {

src/frontend/terminaloverlay.h

@@ -134,7 +134,7 @@ namespace Overlay {
     bool need_countup( uint64_t ts ) const { return ts - last_word_from_server > 6500; }
     void adjust_message( void );
     void apply( Framebuffer &fb ) const;
-    void set_notification_string( const wstring s_message ) { message = s_message; message_expiration = timestamp() + 1000; }
+    void set_notification_string( const wstring &s_message, bool permanent = false ) { message = s_message; if ( permanent ) { message_expiration = -1; } else { message_expiration = timestamp() + 1000; } }
     const wstring &get_notification_string( void ) const { return message; }
     void server_heard( uint64_t s_last_word ) { last_word_from_server = s_last_word; }
     uint64_t get_message_expiration( void ) const { return message_expiration; }

src/network/transportsender.cc

@@ -159,7 +159,9 @@ void TransportSender<MyState>::tick( void )
 template <class MyState>
 void TransportSender<MyState>::send_empty_ack( void )
 {
-  assert ( timestamp() >= next_ack_time );
+  uint64_t now = timestamp();
+
+  assert( now >= next_ack_time );
 
   uint64_t new_num = sent_states.back().num + 1;
 
@@ -169,10 +171,10 @@ void TransportSender<MyState>::send_empty_ack( void )
   }
 
   //  sent_states.push_back( TimestampedState<MyState>( sent_states.back().timestamp, new_num, current_state ) );
-  add_sent_state( sent_states.back().timestamp, new_num, current_state );
+  add_sent_state( now, new_num, current_state );
   send_in_fragments( "", new_num );
 
-  next_ack_time = timestamp() + ACK_INTERVAL;
+  next_ack_time = now + ACK_INTERVAL;
   next_send_time = uint64_t(-1);
 }
 

src/network/transportsender.h

@@ -43,7 +43,7 @@ namespace Network {
     static const int SEND_INTERVAL_MAX = 250; /* ms between frames */
     static const int ACK_INTERVAL = 3000; /* ms between empty acks */
     static const int ACK_DELAY = 100; /* ms before delayed ack */
-    static const int SHUTDOWN_RETRIES = 3; /* number of shutdown packets to send before giving up */
+    static const int SHUTDOWN_RETRIES = 16; /* number of shutdown packets to send before giving up */
     static const int ACTIVE_RETRY_TIMEOUT = 10000; /* attempt to resend at frame rate */
 
     /* helper methods for tick() */