Hi Alicia,
On Mon, Aug 8, 2022 at 2:30 AM Alicia Boya Garcia <ntrrgc@xxxxxxxxx> wrote:
>
> When services, characteristics and descriptors were parsed from DBus
> proxies the client code was calling the print code without initializing
> the `handle` field, which the print functions use.
>
> This resulted in semi-random or zero handles in all attributes when
> using gatt.list-attributes in bluetoothctl, depending on compilation
> flags.
>
> This patch fixes the problem by parsing the handle from the DBus proxy
> path.
> ---
> client/gatt.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/client/gatt.c b/client/gatt.c
> index 4c1efaf75..aaad786b2 100644
> --- a/client/gatt.c
> +++ b/client/gatt.c
> @@ -158,6 +158,16 @@ static void print_inc_service(struct service *service, const char *description)
> service->uuid, text);
> }
>
> +static uint16_t handle_from_path(const char *path)
> +{
> + const char *number = path + strlen(path) - 4;
> +
> + if (number < path)
> + return 0;
> +
> + return (uint16_t) strtol(number, NULL, 16);
> +}
Object paths are subject to change so we shouldn't consider them as
APIs, so what we should aim to do if we really want to expose handles
of remote attributes is to have it as a D-Bus property Handle like we
do for the servers:
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/gatt-api.txt#n53
> static void print_service_proxy(GDBusProxy *proxy, const char *description)
> {
> struct service service;
> @@ -179,6 +189,7 @@ static void print_service_proxy(GDBusProxy *proxy, const char *description)
> service.path = (char *) g_dbus_proxy_get_path(proxy);
> service.uuid = (char *) uuid;
> service.primary = primary;
> + service.handle = handle_from_path(service.path);
>
> print_service(&service, description);
> }
> @@ -261,6 +272,7 @@ static void print_characteristic(GDBusProxy *proxy, const char *description)
> memset(&chrc, 0, sizeof(chrc));
> chrc.path = (char *) g_dbus_proxy_get_path(proxy);
> chrc.uuid = (char *) uuid;
> + chrc.handle = handle_from_path(chrc.path);
>
> print_chrc(&chrc, description);
> }
> @@ -355,6 +367,7 @@ static void print_descriptor(GDBusProxy *proxy, const char *description)
> memset(&desc, 0, sizeof(desc));
> desc.path = (char *) g_dbus_proxy_get_path(proxy);
> desc.uuid = (char *) uuid;
> + desc.handle = handle_from_path(desc.path);
>
> print_desc(&desc, description);
> }
> --
> 2.37.1
>
--
Luiz Augusto von Dentz
