Coverity 20190924 (netdata#6941)

* coverity_20190924: Fix 215633

In the switch the library stops case this pointer is NULL, so
there is not necessity to processed with tests

* coverity_20190924: Fix 338067

The current code tries to copy the same size of the variable, another possible
solution would be to use a function to sanitize the code, I will try this first

* coverity_20190924: Fix 348638

Considering that we are testing the variable value one line above
The division will always happen

* coverity_20190924: Fix 348640

For this specific case we do not have the possibility to have memory
leak, valgrind confirms this, but I am adding a new variable here to the
stack to discard the warning

collectors/apps.plugin/apps_plugin.c

@@ -3521,7 +3521,7 @@ static void send_collected_data_to_netdata(struct target *root, const char *type
     send_BEGIN(type, "uptime_avg", dt);
     for (w = root; w ; w = w->next) {
         if(unlikely(w->exposed && w->processes))
-            send_SET(w->name, w->processes?(w->uptime_sum / w->processes):0);
+            send_SET(w->name, w->uptime_sum / w->processes);
     }
     send_END();
 

daemon/main.c

@@ -719,7 +719,7 @@ int get_system_info(struct rrdhost_system_info *system_info) {
                 }
                 char n[51], v[101];
                 snprintfz(n, 50,"%s",name);
-                snprintfz(v, 101,"%s",value);
+                snprintfz(v, 100,"%s",value);
                 if(unlikely(rrdhost_set_system_info_variable(system_info, n, v))) {
                     info("Unexpected environment variable %s=%s", n, v);
                 }

libnetdata/health/health.c

@@ -136,7 +136,8 @@ int health_silencers_json_read_callback(JSON_ENTRY *e)
                 else if (!strcmp(e->data.string,"DISABLE")) silencers->stype = STYPE_DISABLE_ALARMS;
             } else {
                 debug(D_HEALTH, "JSON: Adding %s=%s", e->name, e->data.string);
-                health_silencers_addparam(e->callback_data, e->name, e->data.string);
+                SILENCER *test = health_silencers_addparam(e->callback_data, e->name, e->data.string);
+                (void)test;
             }
             break;
 

libnetdata/json/jsmn.c

@@ -301,10 +301,12 @@ jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len,
         }
     }
 
-    for (i = parser->toknext - 1; i >= 0; i--) {
-        /* Unmatched opened object or array */
-        if (tokens[i].start != -1 && tokens[i].end == -1) {
-            return JSMN_ERROR_PART;
+    if (tokens) {
+        for (i = parser->toknext - 1; i >= 0; i--) {
+            /* Unmatched opened object or array */
+            if (tokens[i].start != -1 && tokens[i].end == -1) {
+                return JSMN_ERROR_PART;
+            }
         }
     }