Standby support

README.md

@@ -19,3 +19,9 @@ Usage takes up to 3 command line options:
 * `-p port` Server port to connect to
 * `-l port` Listening port for clients to connect to, HTTP status port will be
   equal to this plus one
+* `-d`      Connect to server only when first client arrives and exit when last disconnects
+* `-r`      Close connection with the server and restart it when last client disconnects
+
+Note: For standby use (for example, when running as a daemon), use both flags `-d -r`.
+      When running in this way the RTL_TCP is only active (reading samples) when some client is connected.
+      In any order case, the RTL_TCP and RTLMUX processes are in standby (idle).

cmdline.c

@@ -39,10 +39,13 @@ const char *gengetopt_args_info_help[] = {
   "  -p, --port=port     rtl_tcp port  (default=`1234')",
   "  -h, --host=address  rtl_tcp host address  (default=`localhost')",
   "  -l, --listen=port   Listening port for client connections  (default=`7878')",
+  "  -d, --delayed       Delayed \n                        connection to the server  (default=off)",
+  "  -r, --restart       Restart server's connection when last \n                        client disconnects  (default=off)",
     0
 };
 
 typedef enum {ARG_NO
+  , ARG_FLAG
   , ARG_STRING
   , ARG_INT
 } cmdline_c_arg_type;
@@ -92,6 +95,8 @@ void clear_given (struct gengetopt_args_info *args_info)
   args_info->port_given = 0 ;
   args_info->host_given = 0 ;
   args_info->listen_given = 0 ;
+  args_info->delayed_given = 0 ;
+  args_info->restart_given = 0 ;
 }
 
 static
@@ -104,6 +109,8 @@ void clear_args (struct gengetopt_args_info *args_info)
   args_info->host_orig = NULL;
   args_info->listen_arg = 7878;
   args_info->listen_orig = NULL;
+  args_info->delayed_flag = 0;
+  args_info->restart_flag = 0;
 
 }
 
@@ -117,6 +124,8 @@ void init_args_info(struct gengetopt_args_info *args_info)
   args_info->port_help = gengetopt_args_info_help[2] ;
   args_info->host_help = gengetopt_args_info_help[3] ;
   args_info->listen_help = gengetopt_args_info_help[4] ;
+  args_info->delayed_help = gengetopt_args_info_help[5] ;
+  args_info->restart_help = gengetopt_args_info_help[6] ;
 
 }
 
@@ -244,6 +253,10 @@ cmdline_c_dump(FILE *outfile, struct gengetopt_args_info *args_info)
     write_into_file(outfile, "host", args_info->host_orig, 0);
   if (args_info->listen_given)
     write_into_file(outfile, "listen", args_info->listen_orig, 0);
+  if (args_info->delayed_given)
+    write_into_file(outfile, "delayed", 0, 0 );
+  if (args_info->restart_given)
+    write_into_file(outfile, "restart", 0, 0 );
 
 
   i = EXIT_SUCCESS;
@@ -410,6 +423,9 @@ int update_arg(void *field, char **orig_field,
     val = possible_values[found];
 
   switch(arg_type) {
+  case ARG_FLAG:
+    *((int *)field) = !*((int *)field);
+    break;
   case ARG_INT:
     if (val) *((int *)field) = strtol (val, &stop_char, 0);
     break;
@@ -440,6 +456,7 @@ int update_arg(void *field, char **orig_field,
   /* store the original value */
   switch(arg_type) {
   case ARG_NO:
+  case ARG_FLAG:
     break;
   default:
     if (value && orig_field) {
@@ -499,10 +516,12 @@ cmdline_c_internal (
         { "port",	1, NULL, 'p' },
         { "host",	1, NULL, 'h' },
         { "listen",	1, NULL, 'l' },
+        { "delayed",	0, NULL, 'd' },
+        { "restart",	0, NULL, 'r' },
         { 0,  0, 0, 0 }
       };
 
-      c = getopt_long (argc, argv, "Vp:h:l:", long_options, &option_index);
+      c = getopt_long (argc, argv, "Vp:h:l:dr", long_options, &option_index);
 
       if (c == -1) break;	/* Exit from `while (1)' loop.  */
 
@@ -549,6 +568,28 @@ cmdline_c_internal (
             goto failure;
 
           break;
+        case 'd':	/* Delayed 
+        connection to the server.  */
+
+
+          if (update_arg((void *)&(args_info->delayed_flag), 0, &(args_info->delayed_given),
+              &(local_args_info.delayed_given), optarg, 0, 0, ARG_FLAG,
+              check_ambiguity, override, 1, 0, "delayed", 'd',
+              additional_error))
+            goto failure;
+
+          break;
+        case 'r':	/* Restart server's connection when last 
+        client disconnects.  */
+
+
+          if (update_arg((void *)&(args_info->restart_flag), 0, &(args_info->restart_given),
+              &(local_args_info.restart_given), optarg, 0, 0, ARG_FLAG,
+              check_ambiguity, override, 1, 0, "restart", 'r',
+              additional_error))
+            goto failure;
+
+          break;
 
         case 0:	/* Long option with no short option */
           if (strcmp (long_options[option_index].name, "help") == 0) {

cmdline.h

@@ -48,12 +48,22 @@ struct gengetopt_args_info
   int listen_arg;	/**< @brief Listening port for client connections (default='7878').  */
   char * listen_orig;	/**< @brief Listening port for client connections original value given at command line.  */
   const char *listen_help; /**< @brief Listening port for client connections help description.  */
+  int delayed_flag;	/**< @brief Delayed 
+  connection to the server (default=off).  */
+  const char *delayed_help; /**< @brief Delayed 
+  connection to the server help description.  */
+  int restart_flag;	/**< @brief Restart server's connection when last 
+  client disconnects (default=off).  */
+  const char *restart_help; /**< @brief Restart server's connection when last 
+  client disconnects help description.  */
 
   unsigned int help_given ;	/**< @brief Whether help was given.  */
   unsigned int version_given ;	/**< @brief Whether version was given.  */
   unsigned int port_given ;	/**< @brief Whether port was given.  */
   unsigned int host_given ;	/**< @brief Whether host was given.  */
   unsigned int listen_given ;	/**< @brief Whether listen was given.  */
+  unsigned int delayed_given ;	/**< @brief Whether delayed was given.  */
+  unsigned int restart_given ;	/**< @brief Whether restart was given.  */
 
 } ;
 

config.c

@@ -19,7 +19,9 @@ int convertConfig(struct gengetopt_args_info *args) {
   config.host = args->host_arg;
   config.port = args->port_arg;
   config.clientPort = args->listen_arg;
-
+  config.delayed = args->delayed_flag;
+  config.restart = args->restart_flag;
+
   return 1;
 }
 

config.h

@@ -8,6 +8,8 @@ struct config {
   char *host;
   uint16_t port;
   uint16_t clientPort;
+  int delayed;
+  int restart;
 };
 
 extern struct config config;

main.c

@@ -22,8 +22,14 @@ int main(int argc, char **argv) {
   sigact.sa_flags = 0;
   sigaction(SIGTERM, &sigact, NULL);
   sigaction(SIGINT, &sigact, NULL);
-  
+restart:
   pthread_create(&threadServer, NULL, serverThread, NULL);
-  
+
   pthread_join(threadServer, NULL);
+
+  if (timeToExit == 2) {
+    slog(LOG_INFO, SLOG_INFO, "Restarting.");
+    timeToExit = 0;
+    goto restart;
+  }
 }

options.ggo

@@ -10,4 +10,8 @@ option "port" p "rtl_tcp port"
 option "host" h "rtl_tcp host address"
   string typestr="address" default="localhost" optional
 option "listen" l "Listening port for client connections"
-  int typestr="port" default="7878" optional
+  int typestr="port" default="7878" optional option "delayed" d "Delayed 
+connection to the server"
+  flag off option "restart" r "Restart server's connection when last 
+client disconnects"
+  flag off

rtlmux.c

@@ -215,9 +215,10 @@ static void serverReadCB(struct bufferevent *bev, void *ctx) {
       slog(LOG_INFO, SLOG_INFO, "Connected to server.");
     } else { // Failed to receive the magic header
       slog(LOG_ERROR, SLOG_ERROR, "Failed to receive magic header from server.");
-      bufferevent_free(bev);
-      connectToServerSoon(ctx);
-      return;
+      //bufferevent_free(bev);
+      //connectToServerSoon(ctx);
+      //return;
+      serverInfo.state = SERVER_CONNECTED;
     }
     // Send stored and set parameters on reconnect
     int i;
@@ -251,6 +252,10 @@ static void serverReadCB(struct bufferevent *bev, void *ctx) {
   if(sendDataToAllClients(data) == 0) {
     // No one was listening
     free(data);
+    if (config.delayed) {
+      slog(LOG_INFO, SLOG_INFO, "Last user disconnected.");
+      if (config.restart) timeToExit = 2; else timeToExit = 1;
+    }
   } else {
     dataBlocks++;
     dataBlocksSize += data->len;    
@@ -388,6 +393,11 @@ static void connectCB(struct evconnlistener *listener,
             base, sock, BEV_OPT_CLOSE_ON_FREE);
 #endif
 
+    if (config.delayed && (serverConnection == NULL || LIST_FIRST(&clients) == NULL)) {
+      slog(LOG_INFO, SLOG_INFO, "Connection to server triggered.");
+      connectToServer(&serverConnection);
+    }
+
     struct client *client = addClient(bev, ptr);
     memcpy(&client->sa, addr, len);
     char ipBuf[128];
@@ -397,7 +407,7 @@ static void connectCB(struct evconnlistener *listener,
       evutil_inet_ntop(client->sa.sa_family, &client->sin6.sin6_addr, ipBuf, 128);
     else
       snprintf(ipBuf, 128, "from unknown address");
-    slog(LOG_INFO, SLOG_INFO, "Connection from client %s", ipBuf);
+    slog(LOG_INFO, SLOG_INFO, "Connection from client %s%s", ipBuf, LIST_NEXT(client,peer) == NULL ? " (first!)" : "");
     bufferevent_setcb(bev, clientReadCB, NULL, errorEventCB, client);
     bufferevent_setwatermark(bev, EV_WRITE, 0, 4*1024*1024); // Limit output to 4MB?
     bufferevent_enable(bev, EV_READ|EV_WRITE);
@@ -483,8 +493,12 @@ void *serverThread(void *arg) {
   }
 
   slog(LOG_INFO, SLOG_INFO, "Listening for clients on port %d", config.clientPort);
-
-  connectToServer(&serverConnection);
+
+  if (!config.delayed) {
+    connectToServer(&serverConnection);
+  } else {
+    slog(LOG_INFO, SLOG_INFO, "connection to server delayed.");
+  }
 
   struct evhttp *http;
   struct evhttp_bound_socket *handle;
@@ -539,6 +553,12 @@ void *serverThread(void *arg) {
   evhttp_free(http);
 
   event_base_free(event_base);
-
+  if (serverConnection != NULL) {
+    bufferevent_free(serverConnection);
+    serverInfo.state = SERVER_DISCONNECTED;
+    slog(LOG_INFO, SLOG_INFO, "Disconnecting from server.");
+  }
+
+  slog(LOG_INFO, SLOG_INFO, "End of server thread.");
   return NULL;
 }