[PATCH v2 00/10] gatt: Add AcquireWrite and AcquireNotify

[PATCH v2 00/10] gatt: Add AcquireWrite and AcquireNotify

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This set adds 2 new methods to GattCharacteristics1, thse deal with
attributes that attempts to emulate a byte stream transfer, or a protocol
on top of GATT, using write without response and notifications.

v2:
- Rename WriteLocked and NotifyLocked to WriteAcquired and NotifyAcquired
- Make WriteAcquired and NotifyAcquired optional so they only appear if
the required flags are supported.
- Make sure O_CLOEXEC and O_NONBLOCK are set in the flags passed to pipe2.

Luiz Augusto von Dentz (10):
  doc/gatt-api: Add AcquireWrite and AcquireNotify
  shared/gatt-client: Allow multiple ready callbacks
  gatt: Add implementation of AcquireWrite
  gatt: Add implementation of WriteAcquired
  client: Add acquire-write command
  client: Add release-write command
  gatt: Add implementation of AcquireNotify
  gatt: Add implementation of NotifyAcquired
  client: Add acquire-notify command
  client: Add release-notify command

 Makefile.tools           |   4 +-
 client/gatt.c            | 209 +++++++++++++++++++++++++++
 client/gatt.h            |   6 +
 client/main.c            |  48 +++++++
 doc/gatt-api.txt         |  62 ++++++++
 peripheral/gatt.c        |   4 +-
 src/device.c             |  16 ++-
 src/gatt-client.c        | 367 +++++++++++++++++++++++++++++++++++++++++++++++
 src/shared/gatt-client.c |  60 ++++++--
 src/shared/gatt-client.h |   4 +-
 tools/btgatt-client.c    |   2 +-
 unit/test-gatt.c         |   4 +-
 12 files changed, 759 insertions(+), 27 deletions(-)

-- 
2.9.4

[PATCH v2 01/10] doc/gatt-api: Add AcquireWrite and AcquireNotify

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This enables write and notify exclusive access via file descriptors in
case the characteristic is actually trying to emulate a byte stream
transfer or have a protocol on top of GATT.
---
 doc/gatt-api.txt | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/doc/gatt-api.txt b/doc/gatt-api.txt
index 6c98b87..3f4a3ca 100644
--- a/doc/gatt-api.txt
+++ b/doc/gatt-api.txt
@@ -91,6 +91,56 @@ Methods		array{byte} ReadValue(dict options)
 					 org.bluez.Error.NotAuthorized
 					 org.bluez.Error.NotSupported
 
+		fd, uint16 AcquireWrite() [experimental] (Client only)
+
+			Acquire write file descriptor and MTU and lock
+			write access to the characteristic.
+
+			Only works with characteristic that has
+			WriteAcquired property which relies on
+			write-without-response Flag.
+
+			To release the lock the client shall close the file
+			descriptor, a HUP is generated in case the device
+			is disconnected.
+
+			Note: the MTU can only be negotiated once and is
+			symmetric therefore this method may be delayed in
+			order to have the exchange MTU completed, because of
+			that the file descriptor is closed during
+			reconnections as the MTU has to be renegotiated.
+
+			Possible Errors: org.bluez.Error.Failed
+					 org.bluez.Error.NotSupported
+
+		fd, uint16 AcquireNotify() [experimental] (Client only)
+
+			Acquire notify file descriptor and MTU and lock
+			notifications to the characteristic.
+
+			Only works with characteristic that has NotifyAcquired
+			which relies on notify Flag and no other client have
+			called StartNotify.
+
+			Notification are enabled during this procedure so
+			StartNotify shall not be called, any notification
+			will be dispatched via file descriptor therefore the
+			Value property is no affected during the time where
+			notify has been acquired.
+
+			To release the lock the client shall close the file
+			descriptor, a HUP is generated in case the device
+			is disconnected.
+
+			Note: the MTU can only be negotiated once and is
+			symmetric therefore this method may be delayed in
+			order to have the exchange MTU completed, because of
+			that the file descriptor is closed during
+			reconnections as the MTU has to be renegotiated.
+
+			Possible Errors: org.bluez.Error.Failed
+					 org.bluez.Error.NotSupported
+
 		void StartNotify()
 
 			Starts a notification session from this characteristic
@@ -125,6 +175,18 @@ Properties	string UUID [read-only]
 			when a notification or indication is received, upon
 			which a PropertiesChanged signal will be emitted.
 
+		boolean WriteAcquired [read-only, optional]
+
+			True, if this characteristic has been acquire by any
+			client using AcquireWrite. This properties is ommited
+			in case write-without-response flag is not set.
+
+		boolean NotifyAcquired [read-only, optional]
+
+			True, if this characteristic has been acquire by any
+			client using AcquireNotify. This properties is ommited
+			in case notify flag is not set.
+
 		boolean Notifying [read-only, optional]
 
 			True, if notifications or indications on this
-- 
2.9.4

[PATCH v2 02/10] shared/gatt-client: Allow multiple ready callbacks

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This makes the ready callbacks much more convenient to track when the
client is ready since its is now possible to notify more than on client
at the same time.
---
 peripheral/gatt.c        |  4 ++--
 src/device.c             | 10 ++++----
 src/shared/gatt-client.c | 60 ++++++++++++++++++++++++++++++++++++------------
 src/shared/gatt-client.h |  4 +++-
 tools/btgatt-client.c    |  2 +-
 unit/test-gatt.c         |  4 ++--
 6 files changed, 59 insertions(+), 25 deletions(-)

diff --git a/peripheral/gatt.c b/peripheral/gatt.c
index 4c5531d..5ae19a8 100644
--- a/peripheral/gatt.c
+++ b/peripheral/gatt.c
@@ -145,8 +145,8 @@ static struct gatt_conn *gatt_conn_new(int fd)
 		return NULL;
 	}
 
-	bt_gatt_client_set_ready_handler(conn->client,
-				client_ready_callback, conn, NULL);
+	bt_gatt_client_ready_register(conn->client, client_ready_callback,
+								conn, NULL);
 	bt_gatt_client_set_service_changed(conn->client,
 				client_service_changed_callback, conn, NULL);
 
diff --git a/src/device.c b/src/device.c
index def192f..8cb79df 100644
--- a/src/device.c
+++ b/src/device.c
@@ -226,6 +226,7 @@ struct btd_device {
 	struct gatt_db *db;			/* GATT db cache */
 	struct bt_gatt_client *client;		/* GATT client instance */
 	struct bt_gatt_server *server;		/* GATT server instance */
+	unsigned int gatt_ready_id;
 
 	struct btd_gatt_client *client_dbus;
 
@@ -550,7 +551,7 @@ static void gatt_client_cleanup(struct btd_device *device)
 
 	gatt_cache_cleanup(device);
 	bt_gatt_client_set_service_changed(device->client, NULL, NULL, NULL);
-	bt_gatt_client_set_ready_handler(device->client, NULL, NULL, NULL);
+	bt_gatt_client_ready_unregister(device->client, device->gatt_ready_id);
 	bt_gatt_client_unref(device->client);
 	device->client = NULL;
 }
@@ -4718,10 +4719,11 @@ static void gatt_client_init(struct btd_device *device)
 	 */
 	device_accept_gatt_profiles(device);
 
-	if (!bt_gatt_client_set_ready_handler(device->client,
+	device->gatt_ready_id = bt_gatt_client_ready_register(device->client,
 							gatt_client_ready_cb,
-							device, NULL)) {
-		DBG("Failed to set ready handler");
+							device, NULL);
+	if (!device->gatt_ready_id) {
+		DBG("Failed to register GATT ready callback");
 		gatt_client_cleanup(device);
 		return;
 	}
diff --git a/src/shared/gatt-client.c b/src/shared/gatt-client.c
index fbf90ff..a34b001 100644
--- a/src/shared/gatt-client.c
+++ b/src/shared/gatt-client.c
@@ -51,6 +51,12 @@
 #define GATT_SVC_UUID	0x1801
 #define SVC_CHNGD_UUID	0x2a05
 
+struct ready_cb {
+	bt_gatt_client_callback_t callback;
+	bt_gatt_client_destroy_func_t destroy;
+	void *data;
+};
+
 struct bt_gatt_client {
 	struct bt_att *att;
 	int ref_count;
@@ -58,9 +64,7 @@ struct bt_gatt_client {
 	struct bt_gatt_client *parent;
 	struct queue *clones;
 
-	bt_gatt_client_callback_t ready_callback;
-	bt_gatt_client_destroy_func_t ready_destroy;
-	void *ready_data;
+	struct queue *ready_cbs;
 
 	bt_gatt_client_service_changed_callback_t svc_chngd_callback;
 	bt_gatt_client_destroy_func_t svc_chngd_destroy;
@@ -1097,17 +1101,35 @@ done:
 	discovery_op_complete(op, success, att_ecode);
 }
 
+static void ready_destroy(void *data)
+{
+	struct ready_cb *ready = data;
+
+	if (ready->destroy)
+		ready->destroy(ready->data);
+
+	free(ready);
+}
+
 static void notify_client_ready(struct bt_gatt_client *client, bool success,
 							uint8_t att_ecode)
 {
 	const struct queue_entry *entry;
 
-	if (!client->ready_callback || client->ready)
+	if (client->ready)
 		return;
 
 	bt_gatt_client_ref(client);
 	client->ready = success;
-	client->ready_callback(success, att_ecode, client->ready_data);
+
+	for (entry = queue_get_entries(client->ready_cbs); entry;
+							entry = entry->next) {
+		struct ready_cb *ready = entry->data;
+
+		ready->callback(success, att_ecode, ready->data);
+	}
+
+	queue_remove_all(client->ready_cbs, NULL, NULL, ready_destroy);
 
 	/* Notify clones */
 	for (entry = queue_get_entries(client->clones); entry;
@@ -1731,8 +1753,7 @@ static void bt_gatt_client_free(struct bt_gatt_client *client)
 
 	queue_destroy(client->notify_list, notify_data_cleanup);
 
-	if (client->ready_destroy)
-		client->ready_destroy(client->ready_data);
+	queue_destroy(client->ready_cbs, ready_destroy);
 
 	if (client->debug_destroy)
 		client->debug_destroy(client->debug_data);
@@ -1789,6 +1810,7 @@ static struct bt_gatt_client *gatt_client_new(struct gatt_db *db,
 		goto fail;
 
 	client->clones = queue_new();
+	client->ready_cbs = queue_new();
 	client->long_write_queue = queue_new();
 	client->svc_chngd_queue = queue_new();
 	client->notify_list = queue_new();
@@ -1886,22 +1908,30 @@ bool bt_gatt_client_is_ready(struct bt_gatt_client *client)
 	return (client && client->ready);
 }
 
-bool bt_gatt_client_set_ready_handler(struct bt_gatt_client *client,
+unsigned int bt_gatt_client_ready_register(struct bt_gatt_client *client,
 					bt_gatt_client_callback_t callback,
 					void *user_data,
 					bt_gatt_client_destroy_func_t destroy)
 {
+	struct ready_cb *ready;
+
 	if (!client)
-		return false;
+		return 0;
 
-	if (client->ready_destroy)
-		client->ready_destroy(client->ready_data);
+	ready = new0(struct ready_cb, 1);
+	ready->callback = callback;
+	ready->destroy = destroy;
+	ready->data = user_data;
 
-	client->ready_callback = callback;
-	client->ready_destroy = destroy;
-	client->ready_data = user_data;
+	queue_push_tail(client->ready_cbs, ready);
 
-	return true;
+	return PTR_TO_UINT(ready);
+}
+
+bool bt_gatt_client_ready_unregister(struct bt_gatt_client *client,
+						unsigned int id)
+{
+	return queue_remove(client->ready_cbs, UINT_TO_PTR(id));
 }
 
 bool bt_gatt_client_set_service_changed(struct bt_gatt_client *client,
diff --git a/src/shared/gatt-client.h b/src/shared/gatt-client.h
index aceb570..6d8bf80 100644
--- a/src/shared/gatt-client.h
+++ b/src/shared/gatt-client.h
@@ -57,10 +57,12 @@ typedef void (*bt_gatt_client_service_changed_callback_t)(uint16_t start_handle,
 							void *user_data);
 
 bool bt_gatt_client_is_ready(struct bt_gatt_client *client);
-bool bt_gatt_client_set_ready_handler(struct bt_gatt_client *client,
+unsigned int bt_gatt_client_ready_register(struct bt_gatt_client *client,
 					bt_gatt_client_callback_t callback,
 					void *user_data,
 					bt_gatt_client_destroy_func_t destroy);
+bool bt_gatt_client_ready_unregister(struct bt_gatt_client *client,
+						unsigned int id);
 bool bt_gatt_client_set_service_changed(struct bt_gatt_client *client,
 			bt_gatt_client_service_changed_callback_t callback,
 			void *user_data,
diff --git a/tools/btgatt-client.c b/tools/btgatt-client.c
index f97963e..51bc362 100644
--- a/tools/btgatt-client.c
+++ b/tools/btgatt-client.c
@@ -235,7 +235,7 @@ static struct client *client_create(int fd, uint16_t mtu)
 									NULL);
 	}
 
-	bt_gatt_client_set_ready_handler(cli->gatt, ready_cb, cli, NULL);
+	bt_gatt_client_ready_register(cli->gatt, ready_cb, cli, NULL);
 	bt_gatt_client_set_service_changed(cli->gatt, service_changed_cb, cli,
 									NULL);
 
diff --git a/unit/test-gatt.c b/unit/test-gatt.c
index 15638dc..5d79e94 100644
--- a/unit/test-gatt.c
+++ b/unit/test-gatt.c
@@ -684,8 +684,8 @@ static struct context *create_context(uint16_t mtu, gconstpointer data)
 		bt_gatt_client_set_debug(context->client, print_debug,
 						"bt_gatt_client:", NULL);
 
-		bt_gatt_client_set_ready_handler(context->client,
-						client_ready_cb, context, NULL);
+		bt_gatt_client_ready_register(context->client, client_ready_cb,
+								context, NULL);
 		break;
 	default:
 		break;
-- 
2.9.4

[PATCH v2 03/10] gatt: Add implementation of AcquireWrite

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This implements AcquireWrite creating a pipe and passing the write fd
to the application requesting it:

bluetoothd[29915]: src/gatt-client.c:characteristic_create_pipe() AcquireWrite: sender :1.378 io 0x89cdfe0

The fd is monitored and in case the client decides close it, or exit/crash,
the daemon detects the HUP and cleanup properly:

bluetoothd[29915]: src/gatt-client.c:characteristic_pipe_hup() /org/bluez/hci1/dev_00_1B_DC_07_31_88/service001f/char0020: io 0x89cdfe0
---
 src/device.c      |   8 ++-
 src/gatt-client.c | 161 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 168 insertions(+), 1 deletion(-)

diff --git a/src/device.c b/src/device.c
index 8cb79df..6a9936a 100644
--- a/src/device.c
+++ b/src/device.c
@@ -551,7 +551,13 @@ static void gatt_client_cleanup(struct btd_device *device)
 
 	gatt_cache_cleanup(device);
 	bt_gatt_client_set_service_changed(device->client, NULL, NULL, NULL);
-	bt_gatt_client_ready_unregister(device->client, device->gatt_ready_id);
+
+	if (device->gatt_ready_id > 0) {
+		bt_gatt_client_ready_unregister(device->client,
+						device->gatt_ready_id);
+		device->gatt_ready_id = 0;
+	}
+
 	bt_gatt_client_unref(device->client);
 	device->client = NULL;
 }
diff --git a/src/gatt-client.c b/src/gatt-client.c
index 6c67841..9a660df 100644
--- a/src/gatt-client.c
+++ b/src/gatt-client.c
@@ -24,6 +24,8 @@
 #include <stdbool.h>
 #include <stdint.h>
 #include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
 
 #include <dbus/dbus.h>
 
@@ -37,6 +39,7 @@
 #include "error.h"
 #include "adapter.h"
 #include "device.h"
+#include "src/shared/io.h"
 #include "src/shared/queue.h"
 #include "src/shared/att.h"
 #include "src/shared/gatt-db.h"
@@ -97,6 +100,10 @@ struct characteristic {
 	bt_uuid_t uuid;
 	char *path;
 
+	unsigned int ready_id;
+	DBusMessage *acquire_write;
+	struct io *write_io;
+
 	struct async_dbus_op *read_op;
 	struct async_dbus_op *write_op;
 
@@ -990,6 +997,151 @@ fail:
 	return btd_error_not_supported(msg);
 }
 
+static bool chrc_pipe_read(struct io *io, void *user_data)
+{
+	struct characteristic *chrc = user_data;
+	struct bt_gatt_client *gatt = chrc->service->client->gatt;
+	uint8_t buf[512];
+	int fd = io_get_fd(io);
+	ssize_t bytes_read;
+
+	bytes_read = read(fd, buf, sizeof(buf));
+	if (bytes_read < 0)
+		return false;
+
+	if (!gatt)
+		return false;
+
+	bt_gatt_client_write_without_response(gatt, chrc->value_handle,
+					chrc->props & BT_GATT_CHRC_PROP_AUTH,
+					buf, bytes_read);
+
+	return true;
+}
+
+static void characteristic_destroy_pipe(struct characteristic *chrc,
+							struct io *io)
+{
+	if (io == chrc->write_io) {
+		io_destroy(chrc->write_io);
+		chrc->write_io = NULL;
+	}
+}
+
+static bool characteristic_pipe_hup(struct io *io, void *user_data)
+{
+	struct characteristic *chrc = user_data;
+
+	DBG("%s: io %p", chrc->path, io);
+
+	characteristic_destroy_pipe(chrc, io);
+
+	return false;
+}
+
+static DBusMessage *characteristic_create_pipe(struct characteristic *chrc,
+						DBusMessage *msg)
+{
+	struct bt_gatt_client *gatt = chrc->service->client->gatt;
+	int pipefd[2];
+	struct io *io;
+	bool dir;
+	uint16_t mtu;
+	DBusMessage *reply;
+
+	if (!gatt || !bt_gatt_client_is_ready(gatt))
+		return btd_error_failed(msg, "Not connected");
+
+	if (pipe2(pipefd, O_DIRECT | O_NONBLOCK | O_CLOEXEC) < 0)
+		return btd_error_failed(msg, strerror(errno));
+
+	dir = dbus_message_has_member(msg, "AcquireWrite");
+
+	io = io_new(pipefd[!dir]);
+	if (!io) {
+		close(pipefd[0]);
+		close(pipefd[1]);
+		return btd_error_failed(msg, strerror(EIO));
+	}
+
+	io_set_close_on_destroy(io, true);
+
+	if (!io_set_read_handler(io, chrc_pipe_read, chrc, NULL))
+		goto fail;
+
+	if (!io_set_disconnect_handler(io, characteristic_pipe_hup, chrc, NULL))
+		goto fail;
+
+	mtu = bt_gatt_client_get_mtu(gatt);
+
+	reply = g_dbus_create_reply(msg, DBUS_TYPE_UNIX_FD, &pipefd[dir],
+					DBUS_TYPE_UINT16, &mtu,
+					DBUS_TYPE_INVALID);
+
+	close(pipefd[dir]);
+
+	if (dir)
+		chrc->write_io = io;
+
+	DBG("%s: sender %s io %p", dbus_message_get_member(msg),
+					dbus_message_get_sender(msg), io);
+
+	return reply;
+
+fail:
+	io_destroy(io);
+	close(pipefd[dir]);
+	return btd_error_failed(msg, strerror(EIO));
+}
+
+static void characteristic_ready(bool success, uint8_t ecode, void *user_data)
+{
+	struct characteristic *chrc = user_data;
+	DBusMessage *reply;
+
+	chrc->ready_id = 0;
+
+	if (chrc->acquire_write) {
+		reply = characteristic_create_pipe(chrc, chrc->acquire_write);
+
+		g_dbus_send_message(btd_get_dbus_connection(), reply);
+
+		dbus_message_unref(chrc->acquire_write);
+		chrc->acquire_write = NULL;
+	}
+}
+
+static DBusMessage *characteristic_acquire_write(DBusConnection *conn,
+					DBusMessage *msg, void *user_data)
+{
+	struct characteristic *chrc = user_data;
+	struct bt_gatt_client *gatt = chrc->service->client->gatt;
+
+	if (!gatt)
+		return btd_error_failed(msg, "Not connected");
+
+	if (chrc->write_io || chrc->acquire_write)
+		return btd_error_failed(msg, strerror(EBUSY));
+
+	if (chrc->write_op)
+		return btd_error_in_progress(msg);
+
+	if (!(chrc->props & BT_GATT_CHRC_PROP_WRITE_WITHOUT_RESP))
+		return btd_error_not_supported(msg);
+
+	if (!bt_gatt_client_is_ready(gatt)) {
+		DBG("GATT not ready, wait until it becomes read");
+		if (!chrc->ready_id)
+			chrc->ready_id = bt_gatt_client_ready_register(gatt,
+							characteristic_ready,
+							chrc, NULL);
+		chrc->acquire_write = dbus_message_ref(msg);
+		return NULL;
+	}
+
+	return characteristic_create_pipe(chrc, msg);
+}
+
 struct notify_client {
 	struct characteristic *chrc;
 	int ref_count;
@@ -1265,6 +1417,10 @@ static const GDBusMethodTable characteristic_methods[] = {
 						{ "options", "a{sv}" }),
 					NULL,
 					characteristic_write_value) },
+	{ GDBUS_EXPERIMENTAL_ASYNC_METHOD("AcquireWrite", NULL,
+					GDBUS_ARGS({ "fd", "h" },
+						{ "mtu", "q" }),
+					characteristic_acquire_write) },
 	{ GDBUS_ASYNC_METHOD("StartNotify", NULL, NULL,
 					characteristic_start_notify) },
 	{ GDBUS_METHOD("StopNotify", NULL, NULL,
@@ -1280,6 +1436,11 @@ static void characteristic_free(void *data)
 	queue_destroy(chrc->descs, NULL);
 	queue_destroy(chrc->notify_clients, NULL);
 
+	io_destroy(chrc->write_io);
+
+	if (chrc->acquire_write)
+		dbus_message_unref(chrc->acquire_write);
+
 	g_free(chrc->path);
 	free(chrc);
 }
-- 
2.9.4

[PATCH v2 04/10] gatt: Add implementation of WriteAcquired

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This property indicate if any client has acquire write thus locking the
access to WriteValue.
---
 src/gatt-client.c | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/src/gatt-client.c b/src/gatt-client.c
index 9a660df..9ab5f96 100644
--- a/src/gatt-client.c
+++ b/src/gatt-client.c
@@ -818,6 +818,27 @@ static gboolean characteristic_get_flags(const GDBusPropertyTable *property,
 	return TRUE;
 }
 
+static gboolean
+characteristic_get_write_acquired(const GDBusPropertyTable *property,
+					DBusMessageIter *iter, void *data)
+{
+	struct characteristic *chrc = data;
+	dbus_bool_t locked = chrc->write_io ? TRUE : FALSE;
+
+	dbus_message_iter_append_basic(iter, DBUS_TYPE_BOOLEAN, &locked);
+
+	return TRUE;
+}
+
+static gboolean
+characteristic_write_acquired_exists(const GDBusPropertyTable *property,
+								void *data)
+{
+	struct characteristic *chrc = data;
+
+	return (chrc->props & BT_GATT_CHRC_PROP_WRITE_WITHOUT_RESP);
+}
+
 static void write_characteristic_cb(struct gatt_db_attribute *attr, int err,
 								void *user_data)
 {
@@ -1025,6 +1046,10 @@ static void characteristic_destroy_pipe(struct characteristic *chrc,
 	if (io == chrc->write_io) {
 		io_destroy(chrc->write_io);
 		chrc->write_io = NULL;
+		g_dbus_emit_property_changed(btd_get_dbus_connection(),
+						chrc->path,
+						GATT_CHARACTERISTIC_IFACE,
+						"WriteAcquired");
 	}
 }
 
@@ -1080,8 +1105,13 @@ static DBusMessage *characteristic_create_pipe(struct characteristic *chrc,
 
 	close(pipefd[dir]);
 
-	if (dir)
+	if (dir) {
 		chrc->write_io = io;
+		g_dbus_emit_property_changed(btd_get_dbus_connection(),
+						chrc->path,
+						GATT_CHARACTERISTIC_IFACE,
+						"WriteAcquired");
+	}
 
 	DBG("%s: sender %s io %p", dbus_message_get_member(msg),
 					dbus_message_get_sender(msg), io);
@@ -1406,6 +1436,9 @@ static const GDBusPropertyTable characteristic_properties[] = {
 	{ "Notifying", "b", characteristic_get_notifying, NULL,
 					characteristic_notifying_exists },
 	{ "Flags", "as", characteristic_get_flags, NULL, NULL },
+	{ "WriteAcquired", "b", characteristic_get_write_acquired, NULL,
+				characteristic_write_acquired_exists,
+				G_DBUS_PROPERTY_FLAG_EXPERIMENTAL },
 	{ }
 };
 
-- 
2.9.4

[PATCH v2 05/10] client: Add acquire-write command

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This adds acquire-write command which uses D-Bus AcquireWrite methods
to acquire a file descriptor to write to locking the attribute:

[Test peripheral:/service001f/char0020]# acquire-write
[CHG] Attribute /org/bluez/hci1/dev_00_1B_DC_07_31_88/service001f/char0020 WriteAcquired: yes
AcquireWrite success: fd 7 MTU 65
[Test peripheral:/service001f/char0020]# write 00
Attempting to write fd 7

< ACL Data TX: Handle 3585 flags 0x00 dlen 8
      ATT: Write Command (0x52) len 3
        Handle: 0x0021
          Data: 00
---
 client/gatt.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 client/gatt.h |  2 ++
 client/main.c | 12 ++++++++++
 3 files changed, 87 insertions(+)

diff --git a/client/gatt.c b/client/gatt.c
index 8a4491a..e6f37ae 100644
--- a/client/gatt.c
+++ b/client/gatt.c
@@ -89,6 +89,10 @@ static GList *descriptors;
 static GList *managers;
 static GList *uuids;
 
+static GDBusProxy *write_proxy;
+static int write_fd = -1;
+static uint16_t write_mtu;
+
 static void print_service(struct service *service, const char *description)
 {
 	const char *text;
@@ -236,6 +240,15 @@ void gatt_remove_characteristic(GDBusProxy *proxy)
 	characteristics = g_list_delete_link(characteristics, l);
 
 	print_characteristic(proxy, COLORED_DEL);
+
+	if (write_proxy == proxy) {
+		write_proxy = NULL;
+		write_mtu = 0;
+		if (write_fd > 0) {
+			close(write_fd);
+			write_fd = -1;
+		}
+	}
 }
 
 static void print_desc(struct desc *desc, const char *description)
@@ -619,6 +632,16 @@ static void write_attribute(GDBusProxy *proxy, char *arg)
 	iov.iov_base = value;
 	iov.iov_len = i;
 
+	/* Write using the fd if it has been acquired and fit the MTU */
+	if (proxy == write_proxy && (write_fd > 0 && write_mtu >= i)) {
+		rl_printf("Attempting to write fd %d\n", write_fd);
+		if (writev(write_fd, &iov, 1) < 0) {
+			rl_printf("Failed to write: %s", strerror(errno));
+			return;
+		}
+		return;
+	}
+
 	if (g_dbus_proxy_method_call(proxy, "WriteValue", write_setup,
 					write_reply, &iov, NULL) == FALSE) {
 		rl_printf("Failed to write\n");
@@ -643,6 +666,56 @@ void gatt_write_attribute(GDBusProxy *proxy, const char *arg)
 						g_dbus_proxy_get_path(proxy));
 }
 
+static void acquire_write_reply(DBusMessage *message, void *user_data)
+{
+	DBusError error;
+
+	dbus_error_init(&error);
+
+	if (dbus_set_error_from_message(&error, message) == TRUE) {
+		rl_printf("Failed to acquire write: %s\n", error.name);
+		dbus_error_free(&error);
+		write_proxy = NULL;
+		return;
+	}
+
+	if (write_fd > 0) {
+		close(write_fd);
+		write_fd = -1;
+	}
+
+	write_mtu = 0;
+
+	if ((dbus_message_get_args(message, NULL, DBUS_TYPE_UNIX_FD, &write_fd,
+					DBUS_TYPE_UINT16, &write_mtu,
+					DBUS_TYPE_INVALID) == false)) {
+		rl_printf("Invalid AcquireWrite response\n");
+		return;
+	}
+
+	rl_printf("AcquireWrite success: fd %d MTU %u\n", write_fd, write_mtu);
+}
+
+void gatt_acquire_write(GDBusProxy *proxy, const char *arg)
+{
+	const char *iface;
+
+	iface = g_dbus_proxy_get_interface(proxy);
+	if (strcmp(iface, "org.bluez.GattCharacteristic1")) {
+		rl_printf("Unable to acquire write: %s not a characteristic\n",
+						g_dbus_proxy_get_path(proxy));
+		return;
+	}
+
+	if (g_dbus_proxy_method_call(proxy, "AcquireWrite", NULL,
+				acquire_write_reply, NULL, NULL) == FALSE) {
+		rl_printf("Failed to AcquireWrite\n");
+		return;
+	}
+
+	write_proxy = proxy;
+}
+
 static void notify_reply(DBusMessage *message, void *user_data)
 {
 	bool enable = GPOINTER_TO_UINT(user_data);
diff --git a/client/gatt.h b/client/gatt.h
index 8031a46..713d34f 100644
--- a/client/gatt.h
+++ b/client/gatt.h
@@ -38,6 +38,8 @@ void gatt_read_attribute(GDBusProxy *proxy);
 void gatt_write_attribute(GDBusProxy *proxy, const char *arg);
 void gatt_notify_attribute(GDBusProxy *proxy, bool enable);
 
+void gatt_acquire_write(GDBusProxy *proxy, const char *arg);
+
 void gatt_add_manager(GDBusProxy *proxy);
 void gatt_remove_manager(GDBusProxy *proxy);
 
diff --git a/client/main.c b/client/main.c
index 3af533e..79f61a1 100644
--- a/client/main.c
+++ b/client/main.c
@@ -1799,6 +1799,16 @@ static void cmd_write(const char *arg)
 	gatt_write_attribute(default_attr, arg);
 }
 
+static void cmd_acquire_write(const char *arg)
+{
+	if (!default_attr) {
+		rl_printf("No attribute selected\n");
+		return;
+	}
+
+	gatt_acquire_write(default_attr, arg);
+}
+
 static void cmd_notify(const char *arg)
 {
 	dbus_bool_t enable;
@@ -2274,6 +2284,8 @@ static const struct {
 	{ "read",         NULL,       cmd_read, "Read attribute value" },
 	{ "write",        "<data=[xx xx ...]>", cmd_write,
 						"Write attribute value" },
+	{ "acquire-write", NULL, cmd_acquire_write,
+					"Acquire Write file descriptor" },
 	{ "notify",       "<on/off>", cmd_notify, "Notify attribute value" },
 	{ "register-application", "[UUID ...]", cmd_register_app,
 						"Register profile to connect" },
-- 
2.9.4

[PATCH v2 06/10] client: Add release-write command

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This adds release-write command which closes an existing fd unlocking
the attribute:

[Test peripheral:/service001f/char0020]# release-write
[CHG] Attribute /org/bluez/hci1/dev_00_1B_DC_07_31_88/service001f/char0020 WriteAcquired: no
---
 client/gatt.c | 13 +++++++++++++
 client/gatt.h |  1 +
 client/main.c | 12 ++++++++++++
 3 files changed, 26 insertions(+)

diff --git a/client/gatt.c b/client/gatt.c
index e6f37ae..2756efd 100644
--- a/client/gatt.c
+++ b/client/gatt.c
@@ -716,6 +716,19 @@ void gatt_acquire_write(GDBusProxy *proxy, const char *arg)
 	write_proxy = proxy;
 }
 
+void gatt_release_write(GDBusProxy *proxy, const char *arg)
+{
+	if (proxy != write_proxy || write_fd < 0) {
+		rl_printf("Write not acquired\n");
+		return;
+	}
+
+	write_proxy = NULL;
+	close(write_fd);
+	write_fd = -1;
+	write_mtu = 0;
+}
+
 static void notify_reply(DBusMessage *message, void *user_data)
 {
 	bool enable = GPOINTER_TO_UINT(user_data);
diff --git a/client/gatt.h b/client/gatt.h
index 713d34f..6827057 100644
--- a/client/gatt.h
+++ b/client/gatt.h
@@ -39,6 +39,7 @@ void gatt_write_attribute(GDBusProxy *proxy, const char *arg);
 void gatt_notify_attribute(GDBusProxy *proxy, bool enable);
 
 void gatt_acquire_write(GDBusProxy *proxy, const char *arg);
+void gatt_release_write(GDBusProxy *proxy, const char *arg);
 
 void gatt_add_manager(GDBusProxy *proxy);
 void gatt_remove_manager(GDBusProxy *proxy);
diff --git a/client/main.c b/client/main.c
index 79f61a1..7688a23 100644
--- a/client/main.c
+++ b/client/main.c
@@ -1809,6 +1809,16 @@ static void cmd_acquire_write(const char *arg)
 	gatt_acquire_write(default_attr, arg);
 }
 
+static void cmd_release_write(const char *arg)
+{
+	if (!default_attr) {
+		rl_printf("No attribute selected\n");
+		return;
+	}
+
+	gatt_release_write(default_attr, arg);
+}
+
 static void cmd_notify(const char *arg)
 {
 	dbus_bool_t enable;
@@ -2286,6 +2296,8 @@ static const struct {
 						"Write attribute value" },
 	{ "acquire-write", NULL, cmd_acquire_write,
 					"Acquire Write file descriptor" },
+	{ "release-write", NULL, cmd_release_write,
+					"Release Write file descriptor" },
 	{ "notify",       "<on/off>", cmd_notify, "Notify attribute value" },
 	{ "register-application", "[UUID ...]", cmd_register_app,
 						"Register profile to connect" },
-- 
2.9.4

[PATCH v2 07/10] gatt: Add implementation of AcquireNotify

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This implements AcquireNotify creating a pipe and passing the read fd
to the application requesting it, at same time subscribe for
notifications:

bluetoothd[7279]: src/gatt-client.c:notify_client_ref() owner :1.461
bluetoothd[7279]: src/gatt-client.c:characteristic_create_pipe() AcquireNotify: sender :1.461 io 0x8a60540
---
 src/gatt-client.c | 170 +++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 155 insertions(+), 15 deletions(-)

diff --git a/src/gatt-client.c b/src/gatt-client.c
index 9ab5f96..571d310 100644
--- a/src/gatt-client.c
+++ b/src/gatt-client.c
@@ -89,6 +89,13 @@ struct async_dbus_op {
 	async_dbus_op_complete_t complete;
 };
 
+struct pipe_io {
+	DBusMessage *msg;
+	struct io *io;
+	void (*destroy)(void *data);
+	void *data;
+};
+
 struct characteristic {
 	struct service *service;
 	struct gatt_db_attribute *attr;
@@ -101,8 +108,8 @@ struct characteristic {
 	char *path;
 
 	unsigned int ready_id;
-	DBusMessage *acquire_write;
-	struct io *write_io;
+	struct pipe_io *write_io;
+	struct pipe_io *notify_io;
 
 	struct async_dbus_op *read_op;
 	struct async_dbus_op *write_op;
@@ -1040,16 +1047,31 @@ static bool chrc_pipe_read(struct io *io, void *user_data)
 	return true;
 }
 
+static void pipe_io_destroy(struct pipe_io *io)
+{
+	if (io->destroy)
+		io->destroy(io->data);
+
+	if (io->msg)
+		dbus_message_unref(io->msg);
+
+	io_destroy(io->io);
+	free(io);
+}
+
 static void characteristic_destroy_pipe(struct characteristic *chrc,
 							struct io *io)
 {
-	if (io == chrc->write_io) {
-		io_destroy(chrc->write_io);
+	if (chrc->write_io && io == chrc->write_io->io) {
+		pipe_io_destroy(chrc->write_io);
 		chrc->write_io = NULL;
 		g_dbus_emit_property_changed(btd_get_dbus_connection(),
 						chrc->path,
 						GATT_CHARACTERISTIC_IFACE,
 						"WriteAcquired");
+	} else if (chrc->notify_io) {
+		pipe_io_destroy(chrc->notify_io);
+		chrc->notify_io = NULL;
 	}
 }
 
@@ -1106,12 +1128,13 @@ static DBusMessage *characteristic_create_pipe(struct characteristic *chrc,
 	close(pipefd[dir]);
 
 	if (dir) {
-		chrc->write_io = io;
+		chrc->write_io->io = io;
 		g_dbus_emit_property_changed(btd_get_dbus_connection(),
 						chrc->path,
 						GATT_CHARACTERISTIC_IFACE,
 						"WriteAcquired");
-	}
+	} else
+		chrc->notify_io->io = io;
 
 	DBG("%s: sender %s io %p", dbus_message_get_member(msg),
 					dbus_message_get_sender(msg), io);
@@ -1131,13 +1154,22 @@ static void characteristic_ready(bool success, uint8_t ecode, void *user_data)
 
 	chrc->ready_id = 0;
 
-	if (chrc->acquire_write) {
-		reply = characteristic_create_pipe(chrc, chrc->acquire_write);
+	if (chrc->write_io->msg) {
+		reply = characteristic_create_pipe(chrc, chrc->write_io->msg);
 
 		g_dbus_send_message(btd_get_dbus_connection(), reply);
 
-		dbus_message_unref(chrc->acquire_write);
-		chrc->acquire_write = NULL;
+		dbus_message_unref(chrc->write_io->msg);
+		chrc->write_io->msg = NULL;
+	}
+
+	if (chrc->notify_io->msg) {
+		reply = characteristic_create_pipe(chrc, chrc->notify_io->msg);
+
+		g_dbus_send_message(btd_get_dbus_connection(), reply);
+
+		dbus_message_unref(chrc->notify_io->msg);
+		chrc->notify_io->msg = NULL;
 	}
 }
 
@@ -1150,7 +1182,7 @@ static DBusMessage *characteristic_acquire_write(DBusConnection *conn,
 	if (!gatt)
 		return btd_error_failed(msg, "Not connected");
 
-	if (chrc->write_io || chrc->acquire_write)
+	if (chrc->write_io)
 		return btd_error_failed(msg, strerror(EBUSY));
 
 	if (chrc->write_op)
@@ -1159,13 +1191,15 @@ static DBusMessage *characteristic_acquire_write(DBusConnection *conn,
 	if (!(chrc->props & BT_GATT_CHRC_PROP_WRITE_WITHOUT_RESP))
 		return btd_error_not_supported(msg);
 
+	chrc->write_io = new0(struct pipe_io, 1);
+
 	if (!bt_gatt_client_is_ready(gatt)) {
 		DBG("GATT not ready, wait until it becomes read");
 		if (!chrc->ready_id)
 			chrc->ready_id = bt_gatt_client_ready_register(gatt,
 							characteristic_ready,
 							chrc, NULL);
-		chrc->acquire_write = dbus_message_ref(msg);
+		chrc->write_io->msg = dbus_message_ref(msg);
 		return NULL;
 	}
 
@@ -1338,6 +1372,98 @@ static void register_notify_cb(uint16_t att_ecode, void *user_data)
 	create_notify_reply(op, true, 0);
 }
 
+static void notify_io_cb(uint16_t value_handle, const uint8_t *value,
+					uint16_t length, void *user_data)
+{
+	struct iovec iov;
+	struct notify_client *client = user_data;
+	struct characteristic *chrc = client->chrc;
+	int err;
+
+	/* Drop notification if the pipe is not ready */
+	if (!chrc->notify_io->io)
+		return;
+
+	iov.iov_base = (void *) value;
+	iov.iov_len = length;
+
+	err = io_send(chrc->notify_io->io, &iov, 1);
+	if (err < 0)
+		error("io_send: %s", strerror(-err));
+}
+
+static void register_notify_io_cb(uint16_t att_ecode, void *user_data)
+{
+	struct notify_client *client = user_data;
+	struct characteristic *chrc = client->chrc;
+
+	if (!att_ecode)
+		return;
+
+	queue_remove(chrc->notify_clients, client);
+	notify_client_free(client);
+
+	pipe_io_destroy(chrc->notify_io);
+	chrc->notify_io = NULL;
+}
+
+static void notify_io_destroy(void *data)
+{
+	struct notify_client *client = data;
+
+	queue_remove(client->chrc->notify_clients, client);
+	notify_client_unref(client);
+}
+
+static DBusMessage *characteristic_acquire_notify(DBusConnection *conn,
+					DBusMessage *msg, void *user_data)
+{
+	struct characteristic *chrc = user_data;
+	struct bt_gatt_client *gatt = chrc->service->client->gatt;
+	const char *sender = dbus_message_get_sender(msg);
+	struct notify_client *client;
+
+	if (!gatt)
+		return btd_error_failed(msg, "Not connected");
+
+	/* Each client can only have one active notify session. */
+	if (chrc->notify_io || !queue_isempty(chrc->notify_clients))
+		return btd_error_failed(msg, strerror(EBUSY));
+
+	if (!(chrc->props & BT_GATT_CHRC_PROP_NOTIFY ||
+				chrc->props & BT_GATT_CHRC_PROP_INDICATE))
+		return btd_error_not_supported(msg);
+
+	client = notify_client_create(chrc, sender);
+	if (!client)
+		return btd_error_failed(msg, "Failed allocate notify session");
+
+	client->notify_id = bt_gatt_client_register_notify(gatt,
+						chrc->value_handle,
+						register_notify_io_cb,
+						notify_io_cb,
+						client, NULL);
+	if (!client->notify_id)
+		return btd_error_failed(msg, "Failed to subscribe");
+
+	queue_push_tail(chrc->notify_clients, client);
+
+	chrc->notify_io = new0(struct pipe_io, 1);
+	chrc->notify_io->data = client;
+	chrc->notify_io->destroy = notify_io_destroy;
+
+	if (!bt_gatt_client_is_ready(gatt)) {
+		if (!chrc->ready_id)
+			chrc->ready_id = bt_gatt_client_ready_register(gatt,
+							characteristic_ready,
+							chrc, NULL);
+		chrc->notify_io->msg = dbus_message_ref(msg);
+		return NULL;
+	}
+
+	return characteristic_create_pipe(chrc, msg);
+}
+
 static DBusMessage *characteristic_start_notify(DBusConnection *conn,
 					DBusMessage *msg, void *user_data)
 {
@@ -1347,6 +1473,9 @@ static DBusMessage *characteristic_start_notify(DBusConnection *conn,
 	struct async_dbus_op *op;
 	struct notify_client *client;
 
+	if (chrc->notify_io)
+		return btd_error_failed(msg, strerror(EBUSY));
+
 	if (!(chrc->props & BT_GATT_CHRC_PROP_NOTIFY ||
 				chrc->props & BT_GATT_CHRC_PROP_INDICATE))
 		return btd_error_not_supported(msg);
@@ -1419,6 +1548,12 @@ static DBusMessage *characteristic_stop_notify(DBusConnection *conn,
 	if (!client)
 		return btd_error_failed(msg, "No notify session started");
 
+	if (chrc->notify_io) {
+		pipe_io_destroy(chrc->notify_io);
+		chrc->notify_io = NULL;
+		return dbus_message_new_method_return(msg);
+	}
+
 	queue_remove(chrc->service->client->all_notify_clients, client);
 	bt_gatt_client_unregister_notify(gatt, client->notify_id);
 	update_notifying(chrc);
@@ -1454,6 +1589,10 @@ static const GDBusMethodTable characteristic_methods[] = {
 					GDBUS_ARGS({ "fd", "h" },
 						{ "mtu", "q" }),
 					characteristic_acquire_write) },
+	{ GDBUS_EXPERIMENTAL_ASYNC_METHOD("AcquireNotify", NULL,
+					GDBUS_ARGS({ "fd", "h" },
+						{ "mtu", "q" }),
+					characteristic_acquire_notify) },
 	{ GDBUS_ASYNC_METHOD("StartNotify", NULL, NULL,
 					characteristic_start_notify) },
 	{ GDBUS_METHOD("StopNotify", NULL, NULL,
@@ -1469,10 +1608,11 @@ static void characteristic_free(void *data)
 	queue_destroy(chrc->descs, NULL);
 	queue_destroy(chrc->notify_clients, NULL);
 
-	io_destroy(chrc->write_io);
+	if (chrc->write_io)
+		pipe_io_destroy(chrc->write_io);
 
-	if (chrc->acquire_write)
-		dbus_message_unref(chrc->acquire_write);
+	if (chrc->notify_io)
+		pipe_io_destroy(chrc->notify_io);
 
 	g_free(chrc->path);
 	free(chrc);
-- 
2.9.4

[PATCH v2 08/10] gatt: Add implementation of NotifyAcquired

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This property indicate if any client has acquire notify thus locking the
access to StartNotify.
---
 src/gatt-client.c | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/src/gatt-client.c b/src/gatt-client.c
index 571d310..8f3e60c 100644
--- a/src/gatt-client.c
+++ b/src/gatt-client.c
@@ -846,6 +846,27 @@ characteristic_write_acquired_exists(const GDBusPropertyTable *property,
 	return (chrc->props & BT_GATT_CHRC_PROP_WRITE_WITHOUT_RESP);
 }
 
+static gboolean
+characteristic_get_notify_acquired(const GDBusPropertyTable *property,
+					DBusMessageIter *iter, void *data)
+{
+	struct characteristic *chrc = data;
+	dbus_bool_t locked = chrc->notify_io ? TRUE : FALSE;
+
+	dbus_message_iter_append_basic(iter, DBUS_TYPE_BOOLEAN, &locked);
+
+	return TRUE;
+}
+
+static gboolean
+characteristic_notify_acquired_exists(const GDBusPropertyTable *property,
+								void *data)
+{
+	struct characteristic *chrc = data;
+
+	return (chrc->props & BT_GATT_CHRC_PROP_NOTIFY);
+}
+
 static void write_characteristic_cb(struct gatt_db_attribute *attr, int err,
 								void *user_data)
 {
@@ -1072,6 +1093,10 @@ static void characteristic_destroy_pipe(struct characteristic *chrc,
 	} else if (chrc->notify_io) {
 		pipe_io_destroy(chrc->notify_io);
 		chrc->notify_io = NULL;
+		g_dbus_emit_property_changed(btd_get_dbus_connection(),
+						chrc->path,
+						GATT_CHARACTERISTIC_IFACE,
+						"NotifyAcquired");
 	}
 }
 
@@ -1133,8 +1158,13 @@ static DBusMessage *characteristic_create_pipe(struct characteristic *chrc,
 						chrc->path,
 						GATT_CHARACTERISTIC_IFACE,
 						"WriteAcquired");
-	} else
+	} else {
 		chrc->notify_io->io = io;
+		g_dbus_emit_property_changed(btd_get_dbus_connection(),
+						chrc->path,
+						GATT_CHARACTERISTIC_IFACE,
+						"NotifyAcquired");
+	}
 
 	DBG("%s: sender %s io %p", dbus_message_get_member(msg),
 					dbus_message_get_sender(msg), io);
@@ -1574,6 +1604,9 @@ static const GDBusPropertyTable characteristic_properties[] = {
 	{ "WriteAcquired", "b", characteristic_get_write_acquired, NULL,
 				characteristic_write_acquired_exists,
 				G_DBUS_PROPERTY_FLAG_EXPERIMENTAL },
+	{ "NotifyAcquired", "b", characteristic_get_notify_acquired, NULL,
+				characteristic_notify_acquired_exists,
+				G_DBUS_PROPERTY_FLAG_EXPERIMENTAL },
 	{ }
 };
 
-- 
2.9.4

[PATCH v2 09/10] client: Add acquire-notify command

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This adds acquire-notify command which uses D-Bus AcquireNotify method
to acquire a file descriptor to read notifications locking the attribute:

[Test peripheral:/service001f/char0020]# acquire-notify
[CHG] Attribute /org/bluez/hci1/dev_56_A0_AA_D0_12_FF/service001f/char0020 NotifyAcquired: yes
AcquireNotify success: fd 7 MTU 65

< ACL Data TX: Handle 3585 flags 0x00 dlen 9
      ATT: Write Request (0x12) len 4
        Handle: 0x0022
          Data: 0200

[CHG] /org/bluez/hci1/dev_56_A0_AA_D0_12_FF/service001f/char0020 Notification:
  00

> ACL Data RX: Handle 3585 flags 0x02 dlen 8
      ATT: Handle Value Indication (0x1d) len 3
        Handle: 0x0021
          Data: 00
---
 Makefile.tools |   4 +-
 client/gatt.c  | 163 ++++++++++++++++++++++++++++++++++++++++++++++++---------
 client/gatt.h  |   2 +
 client/main.c  |  12 +++++
 4 files changed, 154 insertions(+), 27 deletions(-)

diff --git a/Makefile.tools b/Makefile.tools
index c0482fb..0fd6dec 100644
--- a/Makefile.tools
+++ b/Makefile.tools
@@ -9,8 +9,8 @@ client_bluetoothctl_SOURCES = client/main.c \
 					client/advertising.c \
 					client/gatt.h client/gatt.c \
 					monitor/uuid.h monitor/uuid.c
-client_bluetoothctl_LDADD = gdbus/libgdbus-internal.la @GLIB_LIBS@ @DBUS_LIBS@ \
-				-lreadline
+client_bluetoothctl_LDADD = gdbus/libgdbus-internal.la src/libshared-glib.la \
+				@GLIB_LIBS@ @DBUS_LIBS@ -lreadline
 endif
 
 if MONITOR
diff --git a/client/gatt.c b/client/gatt.c
index 2756efd..0533854 100644
--- a/client/gatt.c
+++ b/client/gatt.c
@@ -38,6 +38,7 @@
 #include <glib.h>
 
 #include "src/shared/queue.h"
+#include "src/shared/io.h"
 #include "gdbus/gdbus.h"
 #include "monitor/uuid.h"
 #include "display.h"
@@ -90,9 +91,13 @@ static GList *managers;
 static GList *uuids;
 
 static GDBusProxy *write_proxy;
-static int write_fd = -1;
+static struct io *write_io;
 static uint16_t write_mtu;
 
+static GDBusProxy *notify_proxy;
+static struct io *notify_io;
+static uint16_t notify_mtu;
+
 static void print_service(struct service *service, const char *description)
 {
 	const char *text;
@@ -229,6 +234,22 @@ void gatt_add_characteristic(GDBusProxy *proxy)
 	print_characteristic(proxy, COLORED_NEW);
 }
 
+static void notify_io_destroy(void)
+{
+	io_destroy(notify_io);
+	notify_io = NULL;
+	notify_proxy = NULL;
+	notify_mtu = 0;
+}
+
+static void write_io_destroy(void)
+{
+	io_destroy(write_io);
+	write_io = NULL;
+	write_proxy = NULL;
+	write_mtu = 0;
+}
+
 void gatt_remove_characteristic(GDBusProxy *proxy)
 {
 	GList *l;
@@ -241,14 +262,10 @@ void gatt_remove_characteristic(GDBusProxy *proxy)
 
 	print_characteristic(proxy, COLORED_DEL);
 
-	if (write_proxy == proxy) {
-		write_proxy = NULL;
-		write_mtu = 0;
-		if (write_fd > 0) {
-			close(write_fd);
-			write_fd = -1;
-		}
-	}
+	if (write_proxy == proxy)
+		write_io_destroy();
+	else if (notify_proxy == proxy)
+		notify_io_destroy();
 }
 
 static void print_desc(struct desc *desc, const char *description)
@@ -633,9 +650,9 @@ static void write_attribute(GDBusProxy *proxy, char *arg)
 	iov.iov_len = i;
 
 	/* Write using the fd if it has been acquired and fit the MTU */
-	if (proxy == write_proxy && (write_fd > 0 && write_mtu >= i)) {
-		rl_printf("Attempting to write fd %d\n", write_fd);
-		if (writev(write_fd, &iov, 1) < 0) {
+	if (proxy == write_proxy && (write_io && write_mtu >= i)) {
+		rl_printf("Attempting to write fd %d\n", io_get_fd(write_io));
+		if (io_send(write_io, &iov, 1) < 0) {
 			rl_printf("Failed to write: %s", strerror(errno));
 			return;
 		}
@@ -666,9 +683,57 @@ void gatt_write_attribute(GDBusProxy *proxy, const char *arg)
 						g_dbus_proxy_get_path(proxy));
 }
 
+static bool pipe_read(struct io *io, void *user_data)
+{
+	uint8_t buf[512];
+	int fd = io_get_fd(io);
+	ssize_t bytes_read;
+
+	if (io != notify_io)
+		return true;
+
+	bytes_read = read(fd, buf, sizeof(buf));
+	if (bytes_read < 0)
+		return false;
+
+	rl_printf("[" COLORED_CHG "] %s Notification:\n",
+			g_dbus_proxy_get_path(notify_proxy));
+	rl_hexdump(buf, bytes_read);
+
+	return true;
+}
+
+static bool pipe_hup(struct io *io, void *user_data)
+{
+	rl_printf("%s closed\n", io == notify_io ? "Notify" : "Write");
+
+	if (io == notify_io)
+		notify_io_destroy();
+	else
+		write_io_destroy();
+
+	return false;
+}
+
+static struct io *pipe_io_new(int fd)
+{
+	struct io *io;
+
+	io = io_new(fd);
+
+	io_set_close_on_destroy(io, true);
+
+	io_set_read_handler(io, pipe_read, NULL, NULL);
+
+	io_set_disconnect_handler(io, pipe_hup, NULL, NULL);
+
+	return io;
+}
+
 static void acquire_write_reply(DBusMessage *message, void *user_data)
 {
 	DBusError error;
+	int fd;
 
 	dbus_error_init(&error);
 
@@ -679,21 +744,19 @@ static void acquire_write_reply(DBusMessage *message, void *user_data)
 		return;
 	}
 
-	if (write_fd > 0) {
-		close(write_fd);
-		write_fd = -1;
-	}
+	if (write_io)
+		write_io_destroy();
 
-	write_mtu = 0;
-
-	if ((dbus_message_get_args(message, NULL, DBUS_TYPE_UNIX_FD, &write_fd,
+	if ((dbus_message_get_args(message, NULL, DBUS_TYPE_UNIX_FD, &fd,
 					DBUS_TYPE_UINT16, &write_mtu,
 					DBUS_TYPE_INVALID) == false)) {
 		rl_printf("Invalid AcquireWrite response\n");
 		return;
 	}
 
-	rl_printf("AcquireWrite success: fd %d MTU %u\n", write_fd, write_mtu);
+	rl_printf("AcquireWrite success: fd %d MTU %u\n", fd, write_mtu);
+
+	write_io = pipe_io_new(fd);
 }
 
 void gatt_acquire_write(GDBusProxy *proxy, const char *arg)
@@ -718,15 +781,65 @@ void gatt_acquire_write(GDBusProxy *proxy, const char *arg)
 
 void gatt_release_write(GDBusProxy *proxy, const char *arg)
 {
-	if (proxy != write_proxy || write_fd < 0) {
+	if (proxy != write_proxy || !write_io) {
 		rl_printf("Write not acquired\n");
 		return;
 	}
 
-	write_proxy = NULL;
-	close(write_fd);
-	write_fd = -1;
-	write_mtu = 0;
+	write_io_destroy();
+}
+
+static void acquire_notify_reply(DBusMessage *message, void *user_data)
+{
+	DBusError error;
+	int fd;
+
+	dbus_error_init(&error);
+
+	if (dbus_set_error_from_message(&error, message) == TRUE) {
+		rl_printf("Failed to acquire notify: %s\n", error.name);
+		dbus_error_free(&error);
+		write_proxy = NULL;
+		return;
+	}
+
+	if (notify_io) {
+		io_destroy(notify_io);
+		notify_io = NULL;
+	}
+
+	notify_mtu = 0;
+
+	if ((dbus_message_get_args(message, NULL, DBUS_TYPE_UNIX_FD, &fd,
+					DBUS_TYPE_UINT16, &notify_mtu,
+					DBUS_TYPE_INVALID) == false)) {
+		rl_printf("Invalid AcquireWrite response\n");
+		return;
+	}
+
+	rl_printf("AcquireNotify success: fd %d MTU %u\n", fd, notify_mtu);
+
+	notify_io = pipe_io_new(fd);
+}
+
+void gatt_acquire_notify(GDBusProxy *proxy, const char *arg)
+{
+	const char *iface;
+
+	iface = g_dbus_proxy_get_interface(proxy);
+	if (strcmp(iface, "org.bluez.GattCharacteristic1")) {
+		rl_printf("Unable to acquire notify: %s not a characteristic\n",
+						g_dbus_proxy_get_path(proxy));
+		return;
+	}
+
+	if (g_dbus_proxy_method_call(proxy, "AcquireNotify", NULL,
+				acquire_notify_reply, NULL, NULL) == FALSE) {
+		rl_printf("Failed to AcquireNotify\n");
+		return;
+	}
+
+	notify_proxy = proxy;
 }
 
 static void notify_reply(DBusMessage *message, void *user_data)
diff --git a/client/gatt.h b/client/gatt.h
index 6827057..5dba26b 100644
--- a/client/gatt.h
+++ b/client/gatt.h
@@ -41,6 +41,8 @@ void gatt_notify_attribute(GDBusProxy *proxy, bool enable);
 void gatt_acquire_write(GDBusProxy *proxy, const char *arg);
 void gatt_release_write(GDBusProxy *proxy, const char *arg);
 
+void gatt_acquire_notify(GDBusProxy *proxy, const char *arg);
+
 void gatt_add_manager(GDBusProxy *proxy);
 void gatt_remove_manager(GDBusProxy *proxy);
 
diff --git a/client/main.c b/client/main.c
index 7688a23..e0a265d 100644
--- a/client/main.c
+++ b/client/main.c
@@ -1819,6 +1819,16 @@ static void cmd_release_write(const char *arg)
 	gatt_release_write(default_attr, arg);
 }
 
+static void cmd_acquire_notify(const char *arg)
+{
+	if (!default_attr) {
+		rl_printf("No attribute selected\n");
+		return;
+	}
+
+	gatt_acquire_notify(default_attr, arg);
+}
+
 static void cmd_notify(const char *arg)
 {
 	dbus_bool_t enable;
@@ -2298,6 +2308,8 @@ static const struct {
 					"Acquire Write file descriptor" },
 	{ "release-write", NULL, cmd_release_write,
 					"Release Write file descriptor" },
+	{ "acquire-notify", NULL, cmd_acquire_notify,
+					"Acquire Notify file descriptor" },
 	{ "notify",       "<on/off>", cmd_notify, "Notify attribute value" },
 	{ "register-application", "[UUID ...]", cmd_register_app,
 						"Register profile to connect" },
-- 
2.9.4

[PATCH v2 10/10] client: Add release-notify command

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This adds release-notify command which closes an existing fd unlocking
the attribute:

[Test peripheral:/service001f/char0020]# release-notify
[CHG] Attribute /org/bluez/hci1/dev_69_16_5B_9A_06_CD/service001f/char0020 NotifyAcquired: no
---
 client/gatt.c | 10 ++++++++++
 client/gatt.h |  1 +
 client/main.c | 12 ++++++++++++
 3 files changed, 23 insertions(+)

diff --git a/client/gatt.c b/client/gatt.c
index 0533854..33e8936 100644
--- a/client/gatt.c
+++ b/client/gatt.c
@@ -842,6 +842,16 @@ void gatt_acquire_notify(GDBusProxy *proxy, const char *arg)
 	notify_proxy = proxy;
 }
 
+void gatt_release_notify(GDBusProxy *proxy, const char *arg)
+{
+	if (proxy != notify_proxy || !notify_io) {
+		rl_printf("Write not acquired\n");
+		return;
+	}
+
+	notify_io_destroy();
+}
+
 static void notify_reply(DBusMessage *message, void *user_data)
 {
 	bool enable = GPOINTER_TO_UINT(user_data);
diff --git a/client/gatt.h b/client/gatt.h
index 5dba26b..9bab429 100644
--- a/client/gatt.h
+++ b/client/gatt.h
@@ -42,6 +42,7 @@ void gatt_acquire_write(GDBusProxy *proxy, const char *arg);
 void gatt_release_write(GDBusProxy *proxy, const char *arg);
 
 void gatt_acquire_notify(GDBusProxy *proxy, const char *arg);
+void gatt_release_notify(GDBusProxy *proxy, const char *arg);
 
 void gatt_add_manager(GDBusProxy *proxy);
 void gatt_remove_manager(GDBusProxy *proxy);
diff --git a/client/main.c b/client/main.c
index e0a265d..8f75f0e 100644
--- a/client/main.c
+++ b/client/main.c
@@ -1829,6 +1829,16 @@ static void cmd_acquire_notify(const char *arg)
 	gatt_acquire_notify(default_attr, arg);
 }
 
+static void cmd_release_notify(const char *arg)
+{
+	if (!default_attr) {
+		rl_printf("No attribute selected\n");
+		return;
+	}
+
+	gatt_release_notify(default_attr, arg);
+}
+
 static void cmd_notify(const char *arg)
 {
 	dbus_bool_t enable;
@@ -2310,6 +2320,8 @@ static const struct {
 					"Release Write file descriptor" },
 	{ "acquire-notify", NULL, cmd_acquire_notify,
 					"Acquire Notify file descriptor" },
+	{ "release-notify", NULL, cmd_release_notify,
+					"Release Notify file descriptor" },
 	{ "notify",       "<on/off>", cmd_notify, "Notify attribute value" },
 	{ "register-application", "[UUID ...]", cmd_register_app,
 						"Register profile to connect" },
-- 
2.9.4

Re: [PATCH v2 01/10] doc/gatt-api: Add AcquireWrite and AcquireNotify

[Marcel Holtmann]

Hi Luiz,

> This enables write and notify exclusive access via file descriptors in
> case the characteristic is actually trying to emulate a byte stream
> transfer or have a protocol on top of GATT.
> ---
> doc/gatt-api.txt | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 62 insertions(+)
> 
> diff --git a/doc/gatt-api.txt b/doc/gatt-api.txt
> index 6c98b87..3f4a3ca 100644
> --- a/doc/gatt-api.txt
> +++ b/doc/gatt-api.txt
> @@ -91,6 +91,56 @@ Methods		array{byte} ReadValue(dict options)
> 					 org.bluez.Error.NotAuthorized
> 					 org.bluez.Error.NotSupported
> 
> +		fd, uint16 AcquireWrite() [experimental] (Client only)
> +
> +			Acquire write file descriptor and MTU and lock
> +			write access to the characteristic.

Aquire file descriptor and MTU for writing. Usage of WriteValue will be locked ..

Also you need to add an appropriate error code to WriteValue.

> +
> +			Only works with characteristic that has
> +			WriteAcquired property which relies on
> +			write-without-response Flag.
> +
> +			To release the lock the client shall close the file
> +			descriptor, a HUP is generated in case the device
> +			is disconnected.
> +
> +			Note: the MTU can only be negotiated once and is
> +			symmetric therefore this method may be delayed in
> +			order to have the exchange MTU completed, because of
> +			that the file descriptor is closed during
> +			reconnections as the MTU has to be renegotiated.
> +
> +			Possible Errors: org.bluez.Error.Failed
> +					 org.bluez.Error.NotSupported
> +
> +		fd, uint16 AcquireNotify() [experimental] (Client only)
> +
> +			Acquire notify file descriptor and MTU and lock
> +			notifications to the characteristic.

Same as above.

> +
> +			Only works with characteristic that has NotifyAcquired
> +			which relies on notify Flag and no other client have
> +			called StartNotify.
> +
> +			Notification are enabled during this procedure so
> +			StartNotify shall not be called, any notification
> +			will be dispatched via file descriptor therefore the
> +			Value property is no affected during the time where
> +			notify has been acquired.
> +
> +			To release the lock the client shall close the file
> +			descriptor, a HUP is generated in case the device
> +			is disconnected.
> +
> +			Note: the MTU can only be negotiated once and is
> +			symmetric therefore this method may be delayed in
> +			order to have the exchange MTU completed, because of
> +			that the file descriptor is closed during
> +			reconnections as the MTU has to be renegotiated.
> +
> +			Possible Errors: org.bluez.Error.Failed
> +					 org.bluez.Error.NotSupported
> +
> 		void StartNotify()
> 
> 			Starts a notification session from this characteristic
> @@ -125,6 +175,18 @@ Properties	string UUID [read-only]
> 			when a notification or indication is received, upon
> 			which a PropertiesChanged signal will be emitted.
> 
> +		boolean WriteAcquired [read-only, optional]
> +
> +			True, if this characteristic has been acquire by any

has been acquired ..

> +			client using AcquireWrite. This properties is ommited
> +			in case write-without-response flag is not set.
> +
> +		boolean NotifyAcquired [read-only, optional]
> +
> +			True, if this characteristic has been acquire by any

See above.

> +			client using AcquireNotify. This properties is ommited
> +			in case notify flag is not set.
> +
> 		boolean Notifying [read-only, optional]
> 
> 			True, if notifications or indications on this

Otherwise, looks good. Lets get this patch set merged.

Regards

Marcel

Re: [PATCH v2 00/10] gatt: Add AcquireWrite and AcquireNotify

[Luiz Augusto von Dentz]

Hi,

On Tue, Jul 4, 2017 at 6:09 PM, Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
> From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
>
> This set adds 2 new methods to GattCharacteristics1, thse deal with
> attributes that attempts to emulate a byte stream transfer, or a protocol
> on top of GATT, using write without response and notifications.
>
> v2:
> - Rename WriteLocked and NotifyLocked to WriteAcquired and NotifyAcquired
> - Make WriteAcquired and NotifyAcquired optional so they only appear if
> the required flags are supported.
> - Make sure O_CLOEXEC and O_NONBLOCK are set in the flags passed to pipe2.
>
> Luiz Augusto von Dentz (10):
>   doc/gatt-api: Add AcquireWrite and AcquireNotify
>   shared/gatt-client: Allow multiple ready callbacks
>   gatt: Add implementation of AcquireWrite
>   gatt: Add implementation of WriteAcquired
>   client: Add acquire-write command
>   client: Add release-write command
>   gatt: Add implementation of AcquireNotify
>   gatt: Add implementation of NotifyAcquired
>   client: Add acquire-notify command
>   client: Add release-notify command
>
>  Makefile.tools           |   4 +-
>  client/gatt.c            | 209 +++++++++++++++++++++++++++
>  client/gatt.h            |   6 +
>  client/main.c            |  48 +++++++
>  doc/gatt-api.txt         |  62 ++++++++
>  peripheral/gatt.c        |   4 +-
>  src/device.c             |  16 ++-
>  src/gatt-client.c        | 367 +++++++++++++++++++++++++++++++++++++++++++++++
>  src/shared/gatt-client.c |  60 ++++++--
>  src/shared/gatt-client.h |   4 +-
>  tools/btgatt-client.c    |   2 +-
>  unit/test-gatt.c         |   4 +-
>  12 files changed, 759 insertions(+), 27 deletions(-)
>
> --
> 2.9.4

Applied after adjusting documentation according to the review comments.


-- 
Luiz Augusto von Dentz