[Listener] Add option -G (dump configuration)

This new option is just like Aggregator's -G option.

owlps-listener/owlps-listener.h

@@ -31,6 +31,7 @@
 #include <owlps.h>
 #include <owlps-client.h>
 
+#include <stdio.h>
 #include <pcap.h>
 
 #include <sys/param.h>
@@ -70,7 +71,7 @@
 
 
 /* Arguments & program configuration */
-#define OPTIONS "ADf:hH:i:I:Kl:m:n:O:p:P:qr:R:t:T:vVw:" // getopt string
+#define OPTIONS "ADf:GhH:i:I:Kl:m:n:O:p:P:qr:R:t:T:vVw:" // getopt string
 #define DEFAULT_CONFIG_FILE OWL_CONFIG_PREFIX "/owlps-listener.conf"
 enum {MODE_ACTIVE = 'a', MODE_PASSIVE = 'p', MODE_MIXED = 'm'} ;
 #define DEFAULT_AUTOCALIBRATION_HELLO_DELAY 15 // seconds
@@ -174,7 +175,7 @@ int parse_main_options(int argc, char **argv) ;
 int parse_calibration_data(int argc, char **argv) ;
 #endif // OWLPS_LISTENER_USES_PTHREAD
 int check_configuration(void) ;
-void print_configuration(void) ;
+void print_configuration(FILE *stream) ;
 
 #ifdef OWLPS_LISTENER_KEEPS_MONITOR
 void* keep_mode_monitor(void *iface) ;

owlps-listener/owlps-listenerd.c

@@ -20,7 +20,6 @@
 
 #include "owlps-listener.h"
 
-#include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <inttypes.h>
@@ -56,6 +55,13 @@ char *program_name = NULL ;
 uint8_t my_mac_bytes[ETHER_ADDR_LEN] ; // AP MAC address
 char my_ip[INET_ADDRSTRLEN] ; // AP IP address
 
+/* Will we dump the configuration?
+ * Note that we declare this option as a global variable because
+ * it must not appear in Confuse's options (to avoid dumping the
+ * dump_configuration option itself).
+ */
+bool dump_configuration = false ;
+
 pcap_t *capture_handler = NULL ; // Packet capture descriptor
 int aggregation_sockfd ;
 struct sockaddr_in aggregation_server ;
@@ -316,8 +322,20 @@ int initialise_configuration(int argc, char **argv)
   if (! owl_run)
     return ret ;
 
+  /* Configuration dumping */
+  if (dump_configuration)
+    {
+      print_configuration(stdout) ;
+      owl_run = false ;
+      return 0 ;
+    }
+
+  /* Configuration printing */
   if (VERBOSE_INFO)
-    print_configuration() ;
+    {
+      fprintf(stderr, "Configuration:\n") ;
+      print_configuration(stderr) ;
+    }
 
   return 0 ;
 }
@@ -515,6 +533,11 @@ int parse_main_options(int argc, char **argv)
           break ;
         case 'f' : // Config file
           break ; // (already parsed)
+        case 'G' :
+          dump_configuration = true ;
+          /* We must not turn owl_run false here, to avoid the default
+           * check on its value in initialise_configuration(). */
+          break ;
         case 'H' :
 #ifdef OWLPS_LISTENER_USES_PTHREAD
           SET_AUTOCALIBRATION_HELLO_PORT(strtol(optarg, NULL, 0)) ;
@@ -770,13 +793,12 @@ int check_configuration()
 
 
 
-void print_configuration()
+void print_configuration(FILE *stream)
 {
-  fprintf(stderr, "Configuration:\n") ;
 #ifdef OWLPS_LISTENER_USES_CONFIG_FILE
-  cfg_print(cfg, stderr) ;
+  cfg_print(cfg, stream) ;
 #else // OWLPS_LISTENER_USES_CONFIG_FILE
-  fprintf(stderr,
+  fprintf(stream,
           "mode = %c\n"
           "aggregation_ip = \"%s\"\n"
           "aggregation_port = %"PRIuFAST16"\n"
@@ -1617,6 +1639,7 @@ void print_usage()
   printf("Usage :\n"
          "\t%s"
          " [-f config_file]"
+         " [-G]"
          " [-D]"
          " [-v[v[v[v]]] | -q]"
          "\n\t"
@@ -1644,11 +1667,14 @@ void print_usage()
          "\t%s -V\n"
 
          "Main options:\n"
-         "\t-h\t\tPrint this help.\n"
+         "\t-h\t\tPrint this help message and exit.\n"
-         "\t-V\t\tShow version information.\n"
+         "\t-V\t\tShow version information and exit.\n"
          "\t-f config_file\tUse 'config_file' instead of the default"
          " configuration\n\t\t\tfile (%s).\n\t\t\tAvailable only if the"
          " program was linked against\n\t\t\tlibconfuse.\n"
+         "\t-G\t\tDump the configuration on the standard output and exit"
+         "\n\t\t\t(useful to generate a configuration file from the"
+         "\n\t\t\tcurrent set of options).\n"
          "\t-D\t\tDaemon mode.\n"
          "\t-v\t\tBe verbose. You can use this option up to 4 times to"
          "\n\t\t\tincrease the level of verbosity (1 = warnings,"
@@ -1699,7 +1725,7 @@ void print_usage()
          "\t-K\tKeep the monitor mode up on wifi_iface. Use it with"
          " buggy\n\t\tdrivers that disable monitor mode periodically."
          " Available only\n\t\tif the program was compiled with the"
-         " option OWLPS_LISTENER_KEEPS_MONITOR.\n"
+         " option\n\t\tOWLPS_LISTENER_KEEPS_MONITOR.\n"
          ,
          program_name,
          program_name,