examples/nordic_uart: Port to new API

Author: oliviermartin

CMakeLists.txt

@@ -120,7 +120,7 @@ if(GATTLIB_BUILD_EXAMPLES)
   add_subdirectory(examples/read_write)
   #add_subdirectory(examples/read_write_memory)
   add_subdirectory(examples/notification)
-  #add_subdirectory(examples/nordic_uart)
+  add_subdirectory(examples/nordic_uart)
   add_subdirectory(tests/test_continuous_connection)
 
   # Some examples require Bluez code and other DBus support

examples/nordic_uart/nordic_uart.c

@@ -2,7 +2,7 @@
  *
  *  GattLib - GATT Library
  *
- *  Copyright (C) 2016-2021  Olivier Martin <olivier@labapart.org>
+ *  Copyright (C) 2016-2024  Olivier Martin <olivier@labapart.org>
  *
  *
  *  This program is free software; you can redistribute it and/or modify
@@ -22,88 +22,89 @@
  */
 
 #include <assert.h>
+#include <ctype.h>
+#include <pthread.h>
+#include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <signal.h>
 
 #ifdef GATTLIB_LOG_BACKEND_SYSLOG
 #include <syslog.h>
 #endif
 
 #include "gattlib.h"
 
-#define MIN(a,b)	((a)<(b)?(a):(b))
-
 #define NUS_CHARACTERISTIC_TX_UUID	"6e400002-b5a3-f393-e0a9-e50e24dcca9e"
 #define NUS_CHARACTERISTIC_RX_UUID	"6e400003-b5a3-f393-e0a9-e50e24dcca9e"
 
-gattlib_connection_t* m_connection;
+#define BLE_SCAN_TIMEOUT   10
+
+#define MIN(a,b)	((a)<(b)?(a):(b))
 
-void notification_cb(const uuid_t* uuid, const uint8_t* data, size_t data_length, void* user_data) {
-	int i;
+static struct {
+	char *adapter_name;
+	char* mac_address;
+} m_argument;
+
+// Declaration of thread condition variable
+static pthread_cond_t m_connection_terminated = PTHREAD_COND_INITIALIZER;
+
+// declaring mutex
+static pthread_mutex_t m_connection_terminated_lock = PTHREAD_MUTEX_INITIALIZER;
+
+static gattlib_connection_t* m_connection;
+
+static void usage(char *argv[]) {
+	printf("%s <device_address>\n", argv[0]);
+}
+
+static void notification_handler(const uuid_t* uuid, const uint8_t* data, size_t data_length, void* user_data) {
+	uintptr_t i;
+	
 	for(i = 0; i < data_length; i++) {
 		printf("%c", data[i]);
 	}
     fflush(stdout);
 }
 
-static void usage(char *argv[]) {
-	printf("%s <device_address>\n", argv[0]);
-}
-
-void int_handler(int dummy) {
+static void int_handler(int dummy) {
 	gattlib_disconnect(m_connection, false /* wait_disconnection */);
 	exit(0);
 }
 
-int main(int argc, char *argv[]) {
-	char input[256];
-	char* input_ptr;
-	int i, ret, total_length, length = 0;
+static void on_device_connect(gattlib_adapter_t* adapter, const char *dst, gattlib_connection_t* connection, int error, void* user_data) {
 	uuid_t nus_characteristic_tx_uuid;
 	uuid_t nus_characteristic_rx_uuid;
-
-	if (argc != 2) {
-		usage(argv);
-		return 1;
-	}
-
-#ifdef GATTLIB_LOG_BACKEND_SYSLOG
-	openlog("gattlib_nordic_uart", LOG_CONS | LOG_NDELAY | LOG_PERROR, LOG_USER);
-	setlogmask(LOG_UPTO(LOG_INFO));
-#endif
-
-	m_connection = gattlib_connect(NULL, argv[1],
-				       GATTLIB_CONNECTION_OPTIONS_LEGACY_BDADDR_LE_RANDOM |
-				       GATTLIB_CONNECTION_OPTIONS_LEGACY_BT_SEC_LOW);
-	if (m_connection == NULL) {
-		GATTLIB_LOG(GATTLIB_ERROR, "Fail to connect to the bluetooth device.");
-		return 1;
-	}
+	char input[256];
+	char* input_ptr;
+	int ret, total_length, length = 0;
 
 	// Convert characteristics to their respective UUIDs
 	ret = gattlib_string_to_uuid(NUS_CHARACTERISTIC_TX_UUID, strlen(NUS_CHARACTERISTIC_TX_UUID) + 1, &nus_characteristic_tx_uuid);
 	if (ret) {
 		GATTLIB_LOG(GATTLIB_ERROR, "Fail to convert characteristic TX to UUID.");
-		return 1;
+		goto EXIT;
 	}
 	ret = gattlib_string_to_uuid(NUS_CHARACTERISTIC_RX_UUID, strlen(NUS_CHARACTERISTIC_RX_UUID) + 1, &nus_characteristic_rx_uuid);
 	if (ret) {
 		GATTLIB_LOG(GATTLIB_ERROR, "Fail to convert characteristic RX to UUID.");
-		return 1;
+		goto EXIT;
 	}
 
 	// Look for handle for NUS_CHARACTERISTIC_TX_UUID
 	gattlib_characteristic_t* characteristics;
 	int characteristic_count;
-	ret = gattlib_discover_char(m_connection, &characteristics, &characteristic_count);
+	ret = gattlib_discover_char(connection, &characteristics, &characteristic_count);
 	if (ret) {
 		GATTLIB_LOG(GATTLIB_ERROR, "Fail to discover characteristic.");
-		return 1;
+		goto EXIT;
 	}
 
+	//
+	// Confirm the Nordic UART RX and TX GATT characteristics are present
+	//
 	uint16_t tx_handle = 0, rx_handle = 0;
-	for (i = 0; i < characteristic_count; i++) {
+	for (int i = 0; i < characteristic_count; i++) {
 		if (gattlib_uuid_cmp(&characteristics[i].uuid, &nus_characteristic_tx_uuid) == 0) {
 			tx_handle = characteristics[i].value_handle;
 		} else if (gattlib_uuid_cmp(&characteristics[i].uuid, &nus_characteristic_rx_uuid) == 0) {
@@ -112,23 +113,29 @@ int main(int argc, char *argv[]) {
 	}
 	if (tx_handle == 0) {
 		GATTLIB_LOG(GATTLIB_ERROR, "Fail to find NUS TX characteristic.");
-		return 1;
+		goto FREE_GATT_CHARACTERISTICS;
 	} else if (rx_handle == 0) {
 		GATTLIB_LOG(GATTLIB_ERROR, "Fail to find NUS RX characteristic.");
-		return 1;
+		goto FREE_GATT_CHARACTERISTICS;
 	}
-	free(characteristics);
 
-	// Register notification handler
-	gattlib_register_notification(m_connection, notification_cb, NULL);
+	//
+	// Listen for Nordic UART TX GATT characteristic
+	//
+	ret = gattlib_register_notification(connection, notification_handler, NULL);
+	if (ret) {
+		GATTLIB_LOG(GATTLIB_ERROR, "Fail to register notification callback.");
+		goto FREE_GATT_CHARACTERISTICS;
+	}
 
-	ret = gattlib_notification_start(m_connection, &nus_characteristic_rx_uuid);
+	ret = gattlib_notification_start(connection, &nus_characteristic_rx_uuid);
 	if (ret) {
 		GATTLIB_LOG(GATTLIB_ERROR, "Fail to start notification.");
-		return 2;
+		goto FREE_GATT_CHARACTERISTICS;
 	}
 
 	// Register handler to catch Ctrl+C
+	m_connection = connection;
 	signal(SIGINT, int_handler);
 
 	while(1) {
@@ -141,11 +148,97 @@ int main(int argc, char *argv[]) {
 			ret = gattlib_write_without_response_char_by_handle(m_connection, tx_handle, input_ptr, length);
 			if (ret) {
 				GATTLIB_LOG(GATTLIB_ERROR, "Fail to send data to NUS TX characteristic.");
-				return 1;
+				goto FREE_GATT_CHARACTERISTICS;
 			}
 			input_ptr += length;
 		}
 	}
 
+FREE_GATT_CHARACTERISTICS:
+	free(characteristics);
+
+EXIT:
+	gattlib_disconnect(connection, false /* wait_disconnection */);
+
+	pthread_mutex_lock(&m_connection_terminated_lock);
+	pthread_cond_signal(&m_connection_terminated);
+	pthread_mutex_unlock(&m_connection_terminated_lock);
+}
+
+static int stricmp(char const *a, char const *b) {
+    for (;; a++, b++) {
+        int d = tolower((unsigned char)*a) - tolower((unsigned char)*b);
+        if (d != 0 || !*a)
+            return d;
+    }
+}
+
+static void ble_discovered_device(gattlib_adapter_t* adapter, const char* addr, const char* name, void *user_data) {
+	int ret;
+	int16_t rssi;
+
+	if (stricmp(addr, m_argument.mac_address) != 0) {
+		return;
+	}
+
+	ret = gattlib_get_rssi_from_mac(adapter, addr, &rssi);
+	if (ret == 0) {
+		GATTLIB_LOG(GATTLIB_INFO, "Found bluetooth device '%s' with RSSI:%d", m_argument.mac_address, rssi);
+	} else {
+		GATTLIB_LOG(GATTLIB_INFO, "Found bluetooth device '%s'", m_argument.mac_address);
+	}
+
+	ret = gattlib_connect(adapter, addr, GATTLIB_CONNECTION_OPTIONS_NONE, on_device_connect, NULL);
+	if (ret != GATTLIB_SUCCESS) {
+		GATTLIB_LOG(GATTLIB_ERROR, "Failed to connect to the bluetooth device '%s'", addr);
+	}
+}
+
+static void* ble_task(void* arg) {
+	char* addr = arg;
+	gattlib_adapter_t* adapter;
+	int ret;
+
+	ret = gattlib_adapter_open(m_argument.adapter_name, &adapter);
+	if (ret) {
+		GATTLIB_LOG(GATTLIB_ERROR, "Failed to open adapter.");
+		return NULL;
+	}
+
+	ret = gattlib_adapter_scan_enable(adapter, ble_discovered_device, BLE_SCAN_TIMEOUT, addr);
+	if (ret) {
+		GATTLIB_LOG(GATTLIB_ERROR, "Failed to scan.");
+		return NULL;
+	}
+
+	// Wait for the device to be connected
+	pthread_mutex_lock(&m_connection_terminated_lock);
+	pthread_cond_wait(&m_connection_terminated, &m_connection_terminated_lock);
+	pthread_mutex_unlock(&m_connection_terminated_lock);
+
+	return NULL;
+}
+
+int main(int argc, char *argv[]) {
+	int ret;
+
+	if (argc != 2) {
+		usage(argv);
+		return 1;
+	}
+
+#ifdef GATTLIB_LOG_BACKEND_SYSLOG
+	openlog("gattlib_nordic_uart", LOG_CONS | LOG_NDELAY | LOG_PERROR, LOG_USER);
+	setlogmask(LOG_UPTO(LOG_INFO));
+#endif
+
+	m_argument.adapter_name = NULL;
+	m_argument.mac_address = argv[1];
+
+	ret = gattlib_mainloop(ble_task, NULL);
+	if (ret != GATTLIB_SUCCESS) {
+		GATTLIB_LOG(GATTLIB_ERROR, "Failed to create gattlib mainloop");
+	}
+
 	return 0;
 }