[wtp] use goto error exit instead of deep nested if conditions

Convert WTP main() function to linux kernel style goto error exits.

src/wtp/wtp.c

@@ -1396,7 +1396,10 @@ int main(int argc, char** argv) {
 	if (geteuid() != 0) {
 		capwap_logging_fatal("Request root privileges");
 		result = CAPWAP_REQUEST_ROOT;
-	} else {
+
+		goto out_close_log;
+	}
+
 	/* Init random generator */
 	capwap_init_rand();
 
@@ -1404,18 +1407,29 @@ int main(int argc, char** argv) {
 	if (capwap_crypt_init()) {
 		result = CAPWAP_CRYPT_ERROR;
 		capwap_logging_fatal("Error to init crypt engine");
-		} else {
+
+		goto out_check_memory;
+	}
+
 	/* Init WTP */
 	if (!wtp_init()) {
 		result = WTP_ERROR_SYSTEM_FAILER;
 		capwap_logging_fatal("Error to init WTP engine");
-			} else {
+
+		goto out_release_crypto;
+	}
+
 	/* Read configuration file */
 	value = wtp_load_configuration(argc, argv);
 	if (value < 0) {
 		result = WTP_ERROR_LOAD_CONFIGURATION;
 		capwap_logging_fatal("Error to load configuration");
-				} else if (value > 0) {
+
+		goto out_destroy_wtp;
+	} else if (value == 0)
+		/* error already reported in config parser */
+		goto out_destroy_wtp;
+
 	if (!g_wtp.standalone) {
 		capwap_daemon();
 
@@ -1429,7 +1443,11 @@ int main(int argc, char** argv) {
 	wtp_wait_radio_ready();
 
 	/* Connect WTP with kernel module */
-					if (!wtp_kmod_init()) {
+	if (wtp_kmod_init()) {
+		capwap_logging_fatal("Unable to connect with kernel module");
+		goto out_close_radio;
+	}
+
 	capwap_logging_info("SmartCAPWAP kernel module connected");
 
 	/* */
@@ -1450,10 +1468,8 @@ int main(int argc, char** argv) {
 
 	/* */
 	capwap_logging_info("Terminate WTP");
-					} else {
-						capwap_logging_fatal("Unable to connect with kernel module");
-					}
 
+out_close_radio:
 	/* Close radio */
 	wtp_radio_close();
 
@@ -1462,24 +1478,23 @@ int main(int argc, char** argv) {
 		capwap_logging_info("Free wifi binding engine");
 		wifi_driver_free();
 	}
-				}
 
+out_destroy_wtp:
 	/* Free memory */
 	wtp_destroy();
-			}
 
+out_release_crypto:
 	/* Free crypt */
 	capwap_crypt_free();
-		}
 
+out_check_memory:
 	/* Check memory leak */
 	if (capwap_check_memory_leak(1)) {
-			if (result == CAPWAP_SUCCESSFUL) {
+		if (result == CAPWAP_SUCCESSFUL)
 			result = WTP_ERROR_MEMORY_LEAK;
 	}
-		}
-	}
 
+out_close_log:
 	/* Close logging */
 	capwap_logging_close();