Merge pull request #1 from Eltako/bugfix/fix-mdns-nullptr-access

[mdns] Add function to check whether mdns has been startet and a hostname has been set

components/mdns/idf_component.yml

@@ -1,6 +1,6 @@
 version: "1.3.2"
 description: mDNS
-url: https://github.com/espressif/esp-protocols/tree/master/components/mdns
+url: https://github.com/Eltako/esp-protocols/tree/bugfix/fix-mdns-nullptr-access/components/mdns
 dependencies:
   idf:
     version: ">=5.0"

components/mdns/include/mdns.h

@@ -121,6 +121,18 @@ esp_err_t mdns_init(void);
  */
 void mdns_free(void);
 
+/**
+  * @brief  Check whether mDNS is running
+  *
+  */
+ bool mdns_is_initialized();
+
+ /**
+  * @brief  Check whether mDNS has a hostname set
+  *
+  */
+ bool mdns_has_hostname();
+
 /**
  * @brief  Set the hostname for mDNS server
  *         required if you want to advertise services

components/mdns/mdns.c

@@ -56,7 +56,7 @@ static const char *MDNS_SUB_STR = "_sub";
 
 mdns_server_t *_mdns_server = NULL;
 static mdns_host_item_t *_mdns_host_list = NULL;
-static mdns_host_item_t _mdns_self_host;
+static mdns_host_item_t _mdns_self_host = {.hostname = NULL, .address_list = NULL, .next = NULL};
 
 static const char *TAG = "mdns";
 
@@ -5896,6 +5896,14 @@ void mdns_free(void)
     _mdns_server = NULL;
 }
 
+bool mdns_is_initialized() {
+     return _mdns_server != NULL;
+}
+
+bool mdns_has_hostname() {
+     return mdns_is_initialized() && _mdns_server->hostname != NULL &&  _mdns_self_host.hostname != NULL;
+}
+
 esp_err_t mdns_hostname_set(const char *hostname)
 {
     if (!_mdns_server) {