Add rig_lock and rig_unlock to support serial I/O locking for a transaction

https://github.com/Hamlib/Hamlib/issues/695

include/hamlib/rig.h

@@ -3181,6 +3181,10 @@ extern HAMLIB_EXPORT(int) hl_usleep(rig_useconds_t msec);
 
 extern HAMLIB_EXPORT(int) rig_cookie(RIG *rig, enum cookie_e cookie_cmd, char *cookie, int cookie_len);
 
+// two functions globally accessible so rig backends can lock for an I/O transaction
+void rig_lock();
+void rig_unlock();
+
 //! @endcond
 
 __END_DECLS

rigs/dummy/netrigctl.c

@@ -621,6 +621,7 @@ static int netrigctl_open(RIG *rig)
         rs->mode_list |= rs->tx_range_list[i].modes;
         rs->vfo_list |= rs->tx_range_list[i].vfo;
     }
+    if (rs->vfo_list == 0) rs->vfo_list = RIG_VFO_A|RIG_VFO_B;
 
     if (prot_ver == 0) { return RIG_OK; }
 

src/network.c

@@ -445,15 +445,11 @@ void *multicast_server(void *arg)
 
         if (rig->caps->get_freq)
         {
-            sync_callback(1);
             retval = rig_get_freq(rig, RIG_VFO_A, &freqMain);
-            sync_callback(0);
 
             if (retval != RIG_OK) { rig_debug(RIG_DEBUG_ERR, "%s(%d): rig_get_freqA error %s\n", __FILE__, __LINE__, rigerror(retval)); }
 
-            sync_callback(1);
             retval = rig_get_freq(rig, RIG_VFO_B, &freqSub);
-            sync_callback(0);
 
             if (retval != RIG_OK) { rig_debug(RIG_DEBUG_ERR, "%s(%d): rig_get_freqB error %s\n", __FILE__, __LINE__, rigerror(retval)); }
 
@@ -470,15 +466,11 @@ void *multicast_server(void *arg)
 
         if (rig->caps->get_mode)
         {
-            sync_callback(1);
             retval = rig_get_mode(rig, RIG_VFO_A, &modeMain, &widthMain);
-            sync_callback(0);
 
             if (retval != RIG_OK) { rig_debug(RIG_DEBUG_ERR, "%s(%d): rig_get_modeA error %s\n", __FILE__, __LINE__, rigerror(retval)); }
 
-            sync_callback(1);
             retval = rig_get_mode(rig, RIG_VFO_B, &modeSub, &widthSub);
-            sync_callback(0);
 
             if (retval != RIG_OK) { rig_debug(RIG_DEBUG_ERR, "%s(%d): rig_get_modeB error %s\n", __FILE__, __LINE__, rigerror(retval)); }
 
@@ -506,9 +498,7 @@ void *multicast_server(void *arg)
         if (rig->caps->get_split_vfo)
         {
             vfo_t tx_vfo;
-            sync_callback(1);
             retval = rig_get_split_vfo(rig, RIG_VFO_A, &split, &tx_vfo);
-            sync_callback(0);
 
             if (retval != RIG_OK) { rig_debug(RIG_DEBUG_ERR, "%s(%d): rig_get_modeA error %s\n", __FILE__, __LINE__, rigerror(retval)); }
 

src/rig.c

@@ -202,6 +202,31 @@ static const char *const rigerror_table[] =
 
 #define ERROR_TBL_SZ (sizeof(rigerror_table)/sizeof(char *))
 
+#ifdef HAVE_PTHREAD
+// Any call to rig_set or rig_get functions will lock the rig
+// for non-targetable rigs this will still be problematic for rigctld
+// in non-vfo mode as a transaction may be set_vfo/set_x/set_vfo
+// this would require the client to request a lock
+static pthread_mutex_t rig_lock_mutex = PTHREAD_MUTEX_INITIALIZER;
+void rig_lock()
+{
+#ifdef HAVE_PTHREAD
+    pthread_mutex_lock(&rig_lock_mutex);
+    rig_debug(RIG_DEBUG_TRACE, "%s\n", __func__);
+#endif
+}
+void rig_unlock()
+{
+#ifdef HAVE_PTHREAD
+    pthread_mutex_unlock(&rig_lock_mutex);
+    rig_debug(RIG_DEBUG_TRACE, "%s\n", __func__);
+#endif
+}
+#else
+void rig_lock() {};
+void rig_unlock() {};
+#endif
+
 /*
  * track which rig is opened (with rig_open)
  * needed at least for transceive mode