raspberrypi: statically allocate storage for hostname

Author: jepler

ports/raspberrypi/common-hal/wifi/Radio.c

@@ -92,10 +92,10 @@ mp_obj_t common_hal_wifi_radio_get_hostname(wifi_radio_obj_t *self) {
 }
 
 void common_hal_wifi_radio_set_hostname(wifi_radio_obj_t *self, const char *hostname) {
-    self->hostname = mp_obj_new_str(hostname, strlen(hostname));
-    hostname = mp_obj_str_get_str(self->hostname);
-    netif_set_hostname(NETIF_STA, hostname);
-    netif_set_hostname(NETIF_AP, hostname);
+    assert(strlen(hostname) < MP_ARRAY_SIZE(self->hostname));
+    memcpy(self->hostname, hostname, strlen(hostname));
+    netif_set_hostname(NETIF_STA, self->hostname);
+    netif_set_hostname(NETIF_AP, self->hostname);
 }
 
 mp_obj_t common_hal_wifi_radio_get_mac_address(wifi_radio_obj_t *self) {

ports/raspberrypi/common-hal/wifi/Radio.h

@@ -33,7 +33,7 @@
 
 typedef struct {
     mp_obj_base_t base;
-    mp_obj_t hostname;
+    char hostname[254]; // hostname max is 253 chars, + 1 for trailing NUL
     wifi_scannednetworks_obj_t *current_scan;
 } wifi_radio_obj_t;