src/settings.c

// SPDX-License-Identifier: LGPL-2.1-or-later
/*
 *
 *  BlueZ - Bluetooth protocol stack for Linux
 *
 *  Copyright (C) 2022  Intel Corporation.
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdbool.h>
#include <errno.h>

#include <glib.h>

#include "bluetooth/bluetooth.h"
#include "bluetooth/uuid.h"

#include "log.h"
#include "src/shared/queue.h"
#include "src/shared/att.h"
#include "src/shared/gatt-db.h"
#include "settings.h"

#define GATT_PRIM_SVC_UUID_STR "2800"
#define GATT_SND_SVC_UUID_STR  "2801"
#define GATT_INCLUDE_UUID_STR "2802"
#define GATT_CHARAC_UUID_STR "2803"

static ssize_t str2val(const char *str, uint8_t *val, size_t len)
{
	const char *pos = str;
	size_t i;

	for (i = 0; i < len; i++) {
		if (sscanf(pos, "%2hhx", &val[i]) != 1)
			break;
		pos += 2;
	}

	return i;
}

static void load_desc_value(struct gatt_db_attribute *attrib, int err,
							void *user_data)
{
}

static int load_desc(struct gatt_db *db, char *handle, char *value,
					struct gatt_db_attribute *service)
{
	char uuid_str[MAX_LEN_UUID_STR];
	struct gatt_db_attribute *att;
	uint16_t handle_int;
	uint16_t val;
	bt_uuid_t uuid, ext_uuid;

	if (sscanf(handle, "%04hx", &handle_int) != 1) {
		DBG("Failed to parse handle: %s", handle);
		return -EIO;
	}

	/* Check if there is any value stored, otherwise it is just the UUID */
	if (sscanf(value, "%04hx:%36s", &val, uuid_str) != 2) {
		if (sscanf(value, "%36s", uuid_str) != 1) {
			DBG("Failed to parse value: %s", value);
			return -EIO;
		}
		val = 0;
	}

	DBG("loading descriptor handle: 0x%04x, value: 0x%04x, value uuid: %s",
						handle_int, val, uuid_str);

	bt_string_to_uuid(&uuid, uuid_str);
	bt_uuid16_create(&ext_uuid, GATT_CHARAC_EXT_PROPER_UUID);

	/* If it is CEP then it must contain the value */
	if (!bt_uuid_cmp(&uuid, &ext_uuid) && !val)
		return -EIO;

	att = gatt_db_service_insert_descriptor(service, handle_int, &uuid,
							0, NULL, NULL, NULL);
	if (!att || gatt_db_attribute_get_handle(att) != handle_int)
		return -EIO;

	if (val) {
		if (!gatt_db_attribute_write(att, 0, (uint8_t *)&val,
						sizeof(val), 0, NULL,
						load_desc_value, NULL))
			return -EIO;
	}

	return 0;
}

static int load_chrc(struct gatt_db *db, char *handle, char *value,
					struct gatt_db_attribute *service)
{
	uint16_t properties, value_handle, handle_int;
	char uuid_str[MAX_LEN_UUID_STR];
	struct gatt_db_attribute *att;
	char val_str[33];
	uint8_t val[16];
	size_t val_len;
	bt_uuid_t uuid;

	if (sscanf(handle, "%04hx", &handle_int) != 1) {
		DBG("Failed to parse handle: %s", handle);
		return -EIO;
	}

	/* Check if there is any value stored */
	if (sscanf(value, GATT_CHARAC_UUID_STR ":%04hx:%02hx:%32s:%36s",
			&value_handle, &properties, val_str, uuid_str) != 4) {
		if (sscanf(value, GATT_CHARAC_UUID_STR ":%04hx:%02hx:%36s",
				&value_handle, &properties, uuid_str) != 3)
			return -EIO;
		val_len = 0;
	} else
		val_len = str2val(val_str, val, sizeof(val));

	bt_string_to_uuid(&uuid, uuid_str);

	/* Log debug message. */
	DBG("loading characteristic handle: 0x%04x, value handle: 0x%04x, "
				"properties 0x%04x value: %s uuid: %s",
				handle_int, value_handle,
				properties, val_len ? val_str : "", uuid_str);

	att = gatt_db_service_insert_characteristic(service, handle_int,
							value_handle,
							&uuid, 0, properties,
							NULL, NULL, NULL);
	if (!att || gatt_db_attribute_get_handle(att) != value_handle)
		return -EIO;

	if (val_len) {
		if (!gatt_db_attribute_write(att, 0, val, val_len, 0, NULL,
						load_desc_value, NULL))
			return -EIO;
	}

	return 0;
}

static int load_incl(struct gatt_db *db, char *handle, char *value,
					struct gatt_db_attribute *service)
{
	char uuid_str[MAX_LEN_UUID_STR];
	struct gatt_db_attribute *att;
	uint16_t start, end;

	if (sscanf(handle, "%04hx", &start) != 1) {
		DBG("Failed to parse handle: %s", handle);
		return -EIO;
	}

	if (sscanf(value, GATT_INCLUDE_UUID_STR ":%04hx:%04hx:%36s", &start,
							&end, uuid_str) != 3) {
		DBG("Failed to parse value: %s", value);
		return -EIO;
	}

	/* Log debug message. */
	DBG("loading included service: 0x%04x, end: 0x%04x, uuid: %s",
						start, end, uuid_str);

	att = gatt_db_get_attribute(db, start);
	if (!att)
		return -EIO;

	att = gatt_db_service_add_included(service, att);
	if (!att)
		return -EIO;

	return 0;
}

static int load_service(struct gatt_db *db, char *handle, char *value)
{
	struct gatt_db_attribute *att;
	uint16_t start, end;
	char type[MAX_LEN_UUID_STR], uuid_str[MAX_LEN_UUID_STR];
	bt_uuid_t uuid;
	bool primary;

	if (sscanf(handle, "%04hx", &start) != 1) {
		DBG("Failed to parse handle: %s", handle);
		return -EIO;
	}

	if (sscanf(value, "%36[^:]:%04hx:%36s", type, &end, uuid_str) != 3) {
		DBG("Failed to parse value: %s", value);
		return -EIO;
	}

	if (g_str_equal(type, GATT_PRIM_SVC_UUID_STR))
		primary = true;
	else if (g_str_equal(type, GATT_SND_SVC_UUID_STR))
		primary = false;
	else
		return -EIO;

	bt_string_to_uuid(&uuid, uuid_str);

	/* Log debug message. */
	DBG("loading service: 0x%04x, end: 0x%04x, uuid: %s", start, end,
								uuid_str);

	att = gatt_db_insert_service(db, start, &uuid, primary,
							end - start + 1);
	if (!att) {
		DBG("Unable load service into db!");
		return -EIO;
	}

	return 0;
}

static int gatt_db_load(struct gatt_db *db, GKeyFile *key_file, char **keys)
{
	struct gatt_db_attribute *current_service;
	char **handle, *value, type[MAX_LEN_UUID_STR];
	int ret;

	/* first load service definitions */
	for (handle = keys; *handle; handle++) {
		value = g_key_file_get_string(key_file, "Attributes", *handle,
									NULL);

		if (!value || sscanf(value, "%36[^:]:", type) != 1) {
			g_free(value);
			return -EIO;
		}

		if (g_str_equal(type, GATT_PRIM_SVC_UUID_STR) ||
				g_str_equal(type, GATT_SND_SVC_UUID_STR)) {
			ret = load_service(db, *handle, value);
			if (ret) {
				g_free(value);
				return ret;
			}
		}

		g_free(value);
	}

	current_service = NULL;
	/* then fill them with data*/
	for (handle = keys; *handle; handle++) {
		value = g_key_file_get_string(key_file, "Attributes", *handle,
									NULL);

		if (!value || sscanf(value, "%36[^:]:", type) != 1) {
			g_free(value);
			return -EIO;
		}

		if (g_str_equal(type, GATT_PRIM_SVC_UUID_STR) ||
				g_str_equal(type, GATT_SND_SVC_UUID_STR)) {
			uint16_t tmp;
			uint16_t start, end;
			bool primary;
			bt_uuid_t uuid;
			char uuid_str[MAX_LEN_UUID_STR];

			if (sscanf(*handle, "%04hx", &tmp) != 1) {
				g_free(value);
				return -EIO;
			}

			if (current_service)
				gatt_db_service_set_active(current_service,
									true);

			current_service = gatt_db_get_attribute(db, tmp);

			gatt_db_attribute_get_service_data(current_service,
							&start, &end,
							&primary, &uuid);

			bt_uuid_to_string(&uuid, uuid_str, sizeof(uuid_str));
			ret = 0;
		} else if (g_str_equal(type, GATT_INCLUDE_UUID_STR)) {
			ret = load_incl(db, *handle, value, current_service);
		} else if (g_str_equal(type, GATT_CHARAC_UUID_STR)) {
			ret = load_chrc(db, *handle, value, current_service);
		} else {
			ret = load_desc(db, *handle, value, current_service);
		}

		g_free(value);
		if (ret) {
			gatt_db_clear(db);
			return ret;
		}
	}

	if (current_service)
		gatt_db_service_set_active(current_service, true);

	return 0;
}

int btd_settings_gatt_db_load(struct gatt_db *db, const char *filename)
{
	char **keys;
	GKeyFile *key_file;
	GError *gerr = NULL;
	int err;

	key_file = g_key_file_new();
	if (!g_key_file_load_from_file(key_file, filename, 0, &gerr)) {
		DBG("Unable to load key file from %s: (%s)", filename,
								gerr->message);
		g_clear_error(&gerr);
	}

	keys = g_key_file_get_keys(key_file, "Attributes", NULL, NULL);

	if (!keys) {
		g_key_file_free(key_file);
		return -ENOENT;
	}

	err = gatt_db_load(db, key_file, keys);

	g_strfreev(keys);
	g_key_file_free(key_file);

	return err;
}

struct gatt_saver {
	struct gatt_db *db;
	uint16_t ext_props;
	GKeyFile *key_file;
};

static void db_hash_read_value_cb(struct gatt_db_attribute *attrib,
						int err, const uint8_t *value,
						size_t length, void *user_data)
{
	const uint8_t **hash = user_data;

	if (err || (length != 16))
		return;

	*hash = value;
}

static void store_desc(struct gatt_db_attribute *attr, void *user_data)
{
	struct gatt_saver *saver = user_data;
	GKeyFile *key_file = saver->key_file;
	char handle[6], value[100], uuid_str[MAX_LEN_UUID_STR];
	const bt_uuid_t *uuid;
	bt_uuid_t ext_uuid;
	uint16_t handle_num;

	handle_num = gatt_db_attribute_get_handle(attr);
	sprintf(handle, "%04hx", handle_num);

	uuid = gatt_db_attribute_get_type(attr);
	bt_uuid_to_string(uuid, uuid_str, sizeof(uuid_str));

	bt_uuid16_create(&ext_uuid, GATT_CHARAC_EXT_PROPER_UUID);
	if (!bt_uuid_cmp(uuid, &ext_uuid) && saver->ext_props)
		sprintf(value, "%04hx:%s", saver->ext_props, uuid_str);
	else
		sprintf(value, "%s", uuid_str);

	g_key_file_set_string(key_file, "Attributes", handle, value);
}

static void store_chrc(struct gatt_db_attribute *attr, void *user_data)
{
	struct gatt_saver *saver = user_data;
	GKeyFile *key_file = saver->key_file;
	char handle[6], value[100], uuid_str[MAX_LEN_UUID_STR];
	uint16_t handle_num, value_handle;
	uint8_t properties;
	bt_uuid_t uuid, hash_uuid;

	if (!gatt_db_attribute_get_char_data(attr, &handle_num, &value_handle,
						&properties, &saver->ext_props,
						&uuid)) {
		DBG("Unable to locate Characteristic data");
		return;
	}

	sprintf(handle, "%04hx", handle_num);
	bt_uuid_to_string(&uuid, uuid_str, sizeof(uuid_str));

	/* Store Database Hash  value if available */
	bt_uuid16_create(&hash_uuid, GATT_CHARAC_DB_HASH);
	if (!bt_uuid_cmp(&uuid, &hash_uuid)) {
		const uint8_t *hash = NULL;

		attr = gatt_db_get_attribute(saver->db, value_handle);

		gatt_db_attribute_read(attr, 0, BT_ATT_OP_READ_REQ, NULL,
					db_hash_read_value_cb, &hash);
		if (hash)
			sprintf(value, GATT_CHARAC_UUID_STR ":%04hx:%02hhx:"
				"%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx"
				"%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx"
				"%02hhx%02hhx:%s", value_handle, properties,
				hash[0], hash[1], hash[2], hash[3],
				hash[4], hash[5], hash[6], hash[7],
				hash[8], hash[9], hash[10], hash[11],
				hash[12], hash[13], hash[14], hash[15],
				uuid_str);
		else
			sprintf(value, GATT_CHARAC_UUID_STR ":%04hx:%02hhx:%s",
				value_handle, properties, uuid_str);

	} else
		sprintf(value, GATT_CHARAC_UUID_STR ":%04hx:%02hhx:%s",
				value_handle, properties, uuid_str);

	g_key_file_set_string(key_file, "Attributes", handle, value);

	gatt_db_service_foreach_desc(attr, store_desc, saver);
}

static void store_incl(struct gatt_db_attribute *attr, void *user_data)
{
	struct gatt_saver *saver = user_data;
	GKeyFile *key_file = saver->key_file;
	struct gatt_db_attribute *service;
	char handle[6], value[100], uuid_str[MAX_LEN_UUID_STR];
	uint16_t handle_num, start, end;
	bt_uuid_t uuid;

	if (!gatt_db_attribute_get_incl_data(attr, &handle_num, &start, &end)) {
		DBG("Unable to locate Included data");
		return;
	}

	service = gatt_db_get_attribute(saver->db, start);
	if (!service) {
		DBG("Unable to locate Included Service");
		return;
	}

	sprintf(handle, "%04hx", handle_num);

	gatt_db_attribute_get_service_uuid(service, &uuid);
	bt_uuid_to_string(&uuid, uuid_str, sizeof(uuid_str));
	sprintf(value, GATT_INCLUDE_UUID_STR ":%04hx:%04hx:%s", start,
								end, uuid_str);

	g_key_file_set_string(key_file, "Attributes", handle, value);
}

static void store_service(struct gatt_db_attribute *attr, void *user_data)
{
	struct gatt_saver *saver = user_data;
	GKeyFile *key_file = saver->key_file;
	char uuid_str[MAX_LEN_UUID_STR], handle[6], value[256];
	uint16_t start, end;
	bt_uuid_t uuid;
	bool primary;
	char *type;

	if (!gatt_db_attribute_get_service_data(attr, &start, &end, &primary,
								&uuid)) {
		DBG("Unable to locate Service data");
		return;
	}

	sprintf(handle, "%04hx", start);

	bt_uuid_to_string(&uuid, uuid_str, sizeof(uuid_str));

	if (primary)
		type = GATT_PRIM_SVC_UUID_STR;
	else
		type = GATT_SND_SVC_UUID_STR;

	sprintf(value, "%s:%04hx:%s", type, end, uuid_str);

	g_key_file_set_string(key_file, "Attributes", handle, value);

	gatt_db_service_foreach_incl(attr, store_incl, saver);
	gatt_db_service_foreach_char(attr, store_chrc, saver);
}

void btd_settings_gatt_db_store(struct gatt_db *db, const char *filename)
{
	GKeyFile *key_file;
	GError *gerr = NULL;
	char *data;
	gsize length = 0;
	struct gatt_saver saver;

	key_file = g_key_file_new();
	if (!g_key_file_load_from_file(key_file, filename, 0, &gerr)) {
		DBG("Unable to load key file from %s: (%s)", filename,
								gerr->message);
		g_clear_error(&gerr);
	}

	/* Remove current attributes since it might have changed */
	g_key_file_remove_group(key_file, "Attributes", NULL);

	saver.key_file = key_file;
	saver.db = db;

	gatt_db_foreach_service(db, NULL, store_service, &saver);

	data = g_key_file_to_data(key_file, &length, NULL);
	if (!g_file_set_contents(filename, data, length, &gerr)) {
		DBG("Unable set contents for %s: (%s)", filename,
								gerr->message);
		g_error_free(gerr);
	}

	g_free(data);
	g_key_file_free(key_file);
}