Prevent segfault in rig_get_caps_int/cptr calls

src/misc.c

@@ -986,6 +986,7 @@ int check_level_param(RIG *rig, setting_t level, value_t val, gran_t **gran)
 
         /* If min==max==step==0, all values are OK here */
         maxval = this_gran->max.f;
+
         if (this_gran->min.f == 0.0f && maxval == 0.0f)
         {
             /* if step==0 also, we're good */
@@ -993,6 +994,7 @@ int check_level_param(RIG *rig, setting_t level, value_t val, gran_t **gran)
             {
                 return RIG_OK;
             }
+
             /* non-zero step, check for max of 1.0 */
             maxval = 1.0f;
         }
@@ -2560,7 +2562,15 @@ long long HAMLIB_API rig_get_caps_int(rig_model_t rig_model,
                                       enum rig_caps_int_e rig_caps)
 {
     const struct rig_caps *caps = rig_get_caps(rig_model);
-    rig_debug(RIG_DEBUG_TRACE, "%s: getting rig_caps for model=%d, rig_caps=%d\n", __func__, rig_model, rig_caps);
+    rig_debug(RIG_DEBUG_TRACE, "%s: getting rig_caps for model=%d, rig_caps=%d\n",
+              __func__, rig_model, rig_caps);
+
+    if (caps == NULL)
+    {
+        rig_debug(RIG_DEBUG_ERR, "%s: called with NULL caps...returning -1\n",
+                  __func__);
+        return -1;
+    }
 
     switch (rig_caps)
     {
@@ -2591,6 +2601,13 @@ const char *HAMLIB_API rig_get_caps_cptr(rig_model_t rig_model,
 {
     const struct rig_caps *caps = rig_get_caps(rig_model);
 
+    if (caps == NULL)
+    {
+        rig_debug(RIG_DEBUG_ERR, "%s: called with NULL caps...returning NULL\n",
+                  __func__);
+        return NULL;
+    }
+
     switch (rig_caps)
     {
     case RIG_CAPS_VERSION_CPTR: