app_init: check Wifi ready by looking up hostname

user/user_main.c

@@ -1,7 +1,52 @@
 #include <esp8266.h>
-#include <config.h>
+#include "config.h"
+#include "syslog.h"
+#include "ems.h"
+
+#define APPINIT_DBG
+#ifdef APPINIT_DBG
+#define DBG(format, ...) do { os_printf(format, ## __VA_ARGS__); } while(0)
+#else
+#define DBG(format, ...) do { } while(0)
+#endif
+
+static struct espconn *pespconn = NULL;
+static ip_addr_t addr;
+static char host[32];
+
+/******************************************************************************
+ *
+ ******************************************************************************/
+static void ICACHE_FLASH_ATTR appinit_gethostbyname_cb(const char *name, ip_addr_t *ipaddr, void *arg)
+{
+    os_free(((struct espconn *)arg)->proto.udp);
+    os_free((struct espconn *)arg);
+
+    if (ipaddr != NULL) {
+	emsInit();
+	EMSBusStatus |= EMSBUS_RDY;
+	DBG("app_init: EMSBus ready...\n");
+    } else {
+	pespconn = (espconn *)os_zalloc(sizeof(espconn));
+	pespconn->proto.udp = (esp_udp *)os_zalloc(sizeof(esp_udp));
+
+	espconn_gethostbyname(pespconn, host, &addr, appinit_gethostbyname_cb);
+	DBG("app_init: retry to resolve %s...\n", host);
+    }
+}
 
 // initialize the custom stuff that goes beyond esp-link
+// we simply try to resolve <hostname.local>
 void app_init() {
 
+    if (pespconn == NULL)
+      pespconn = (espconn *)os_zalloc(sizeof(espconn));
+
+    if (pespconn->proto.udp == NULL)
+      pespconn->proto.udp = (esp_udp *)os_zalloc(sizeof(esp_udp));
+
+    os_sprintf(host, "%s", flashConfig.hostname);
+    DBG("app_init: resolving %s...\n", host);
+
+    espconn_gethostbyname(pespconn, host, &addr, appinit_gethostbyname_cb);
 }