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From:   Barry Byford <31baz66@gmail.com>
Date:   Sat, 20 Jul 2019 17:44:15 +0100
Message-ID: <CAAu3APZ4n9Cc4RJ40Oca0iKchOSNifd=DbzHG_9XPtv9dr1+BQ@mail.gmail.com>
Subject: Re: DBus LEAdvertisement and Python
To:     Bluez mailing list <linux-bluetooth@vger.kernel.org>
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Hello,

I have done a little more investigation on this. The difference in
behaviour between the working library and the failing library comes
down to this line in the BlueZ source.
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/gdbus/client.c#n720
which is called from:
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/src/advertising.c#n1020
It appears g_hash_table_lookup is returning NULL.
I am not familiar with C and have been doing this investigation with
fprintf statements. I don't know how to get the values of
"proxy->prop_list" and "name". Does anyone know how I can print these
values out?
Even better would be, if someone could point me at to what this
relates to in the Python LE Advertisement setup through DBus.
I've looked up the g_hash_table_lookup command:
https://developer.gnome.org/glib/stable/glib-Hash-Tables.html#g-hash-table-lookup
but this hasn't helped me.

Thanks,
Barry

On Thu, 18 Jul 2019 at 22:04, Barry Byford <31baz66@gmail.com> wrote:
>
> Hello Luiz,
>
> Thanks for the prompt response. Below are some updates following your input.
>
> On Thu, 18 Jul 2019 at 09:26, Luiz Augusto von Dentz
> <luiz.dentz@gmail.com> wrote:
> >
> > Hi Barry,
> >
> > On Thu, Jul 18, 2019 at 10:03 AM Barry Byford <31baz66@gmail.com> wrote:
> > >
> > > Hello,
> > >
> > > The Python examples provided in the test directory of the BlueZ
> > > repository use the python-dbus library. Looking at the documentation
> > > of that library it does start by raising concerns and offering
> > > alternatives. I have been looking at some of the alternatives and am
> > > having difficultly getting them to work with BlueZ. I have been
> > > focusing on the org.bluez.LEAdvertisement1 interface.
> > >
> > > Looking at the documentation, it says the service, interface and
> > > object details are:
> > > Service org.bluez
> > > Interface org.bluez.LEAdvertisement1
> > > Object path freely definable
> > >
> > > I am not being successful at publishing to the org.bluez service. It
> > > is also not where the current examples publish to.
> > > Looking at the GattProfile1 documentation, it has service and object
> > > as application dependant.
> > > Service <application dependent>
> > > Interface org.bluez.GattProfile1
> > > Object path <application dependent>
> > > Should the documentation of Service on LEAdvertisement1 be freely
> > > definable also?
> >
> > Yep, the bus name is up to the application which usually don't
> > register a friendly name if you try to register with 'org.bluez' it
> > would probably conflict with the daemon itself so you wouldn't be able
> > to register that name anyway.
> >
> > > I have created the LEAdvertisement1 interface so that it has an
> > > ObjectManager and is introspectable. When I pass the object to
> > > RegisterAdvertisement on the org.bluez.LEAdvertisingManager1 interface
> > > it accepts it (does not give an error) but does not register the data
> > > and I see no advertisement appear. Is there somewhere I can find a
> > > more detailed description of what needs to be on the
> > > org.bluez.LEAdvertisement1 interface that will work with
> > > RegisterAdvertisement?
> >
> > Do you have the bluetoothd output when you register, I get the
> > following when using bluetoothctl:
> >
> > bluetooth]# power on
> > Changing power on succeeded
> > [bluetooth]# advertise on
> > [CHG] Controller B8:8A:60:D8:17:D7 SupportedInstances: 0x04
> > [CHG] Controller B8:8A:60:D8:17:D7 ActiveInstances: 0x01
> > Advertising object registered
> > Tx Power: off
> > Name: off
> > Apperance: off
> > Discoverable: off
> > [bluetooth]#
>
> Using the new dbus library I get:
> Log from bluetoothctl:
> [CHG] Controller FC:F8:AE:8F:0C:A4 SupportedInstances: 0x04
> [CHG] Controller FC:F8:AE:8F:0C:A4 ActiveInstances: 0x01
>
> From the bluetoothd log:
> bluetoothd[2856]: src/advertising.c:register_advertisement()
> RegisterAdvertisement
> bluetoothd[2856]: src/advertising.c:client_create() Adding proxy for
> /ukBaz/bluezero/advertisement1
> bluetoothd[2856]: src/advertising.c:register_advertisement()
> Registered advertisement at path /ukBaz/bluezero/advertisement1
> bluetoothd[2856]: src/advertising.c:refresh_adv() Refreshing
> advertisement: /ukBaz/bluezero/advertisement1
> bluetoothd[2856]: src/advertising.c:add_adv_callback() Advertisement
> registered: /ukBaz/bluezero/advertisement1
>
>
> With the old pyton-dbus library (that is working) I get:
> log from bluetoothctl:
> [CHG] Controller FC:F8:AE:8F:0C:A4 SupportedInstances: 0x04
> [CHG] Controller FC:F8:AE:8F:0C:A4 ActiveInstances: 0x01
>
> From the bluetoothd log:
> bluetoothd[2856]: src/advertising.c:register_advertisement()
> RegisterAdvertisement
> bluetoothd[2856]: src/advertising.c:client_create() Adding proxy for
> /ukBaz/bluezero/advertisement0001
> bluetoothd[2856]: src/advertising.c:register_advertisement()
> Registered advertisement at path /ukBaz/bluezero/advertisement0001
> bluetoothd[2856]: src/advertising.c:parse_service_uuids() Adding
> ServiceUUID: FEAA
> bluetoothd[2856]: src/advertising.c:parse_service_data() Adding
> ServiceData for FEAA
> bluetoothd[2856]: src/advertising.c:refresh_adv() Refreshing
> advertisement: /ukBaz/bluezero/advertisement0001
> bluetoothd[2856]: src/advertising.c:add_adv_callback() Advertisement
> registered: /ukBaz/bluezero/advertisement0001
>
>
> >
> > bluetoothd[6103]: src/advertising.c:client_create() Adding proxy for
> > /org/bluez/advertising
> > bluetoothd[6103]: src/advertising.c:register_advertisement()
> > Registered advertisement at path /org/bluez/advertising
> > bluetoothd[6103]: src/advertising.c:refresh_adv() Refreshing
> > advertisement: /org/bluez/advertising
> > bluetoothd[6103]: src/advertising.c:add_adv_callback() Advertisement
> > registered: /org/bluez/advertising
> >
> >
> > > For reference, I have put below what I am currently  putting on the
> > > org.bluez.LEAdvertisement1 interface.
> > >
> > > Thanks,
> > > Barry
> > >
> > >
> > > $ busctl call ukBaz.bluezero /ukBaz/bluezero/advertisement1
> > > org.freedesktop.DBus.ObjectManager GetManagedObjects
> > > a{oa{sa{sv}}} 1 "/ukBaz/bluezero/advertisement1" 5
> > > "org.freedesktop.DBus.Properties" 0
> > > "org.freedesktop.DBus.Introspectable" 0 "org.freedesktop.DBus.Peer" 0
> > > "org.freedesktop.DBus.ObjectManager" 0 "org.bluez.LEAdvertisement1" 6
> > > "Type" s "broadcast" "ServiceUUIDs" as 0 "ManufacturerData" a{sv} 0
> > > "SolicitUUIDs" as 0 "ServiceData" a{sv} 1 "FEAA" ay 18 16 8 3 117 107
> > > 66 97 122 46 103 105 116 104 117 98 46 105 111 "IncludeTxPower" b
> > > false
> >
> > Not sure if that is the problem but usually ObjectManager is suppose
> > to be on the '/' (root) path.
>
> Good point. It is not clear (to me anyway) exactly what the
> requirement is from reading the spec
> https://dbus.freedesktop.org/doc/dbus-specification.html#standard-interfaces-objectmanager
> I have moved the object manager to the root (/) but this does not seem
> to have changed anything.
>
> $ busctl call ukBaz.bluezero / org.freedesktop.DBus.ObjectManager
> GetManagedObjects
> a{oa{sa{sv}}} 1 "/ukBaz/bluezero/advertisement1" 4
> "org.freedesktop.DBus.Properties" 0
> "org.freedesktop.DBus.Introspectable" 0 "org.freedesktop.DBus.Peer" 0
> "org.bluez.LEAdvertisement1" 6 "Type" s "broadcast" "ServiceUUIDs" as
> 0 "ManufacturerData" a{sv} 0 "SolicitUUIDs" as 0 "ServiceData" a{sv} 1
> "FEAA" ay 18 16 8 3 117 107 66 97 122 46 103 105 116 104 117 98 46 105
> 111 "IncludeTxPower" b false
>
>
> >
> > > $ busctl call ukBaz.bluezero /ukBaz/bluezero/advertisement1
> > > org.freedesktop.DBus.Properties GetAll s org.bluez.LEAdvertisement1
> > > a{sv} 6 "Type" s "broadcast" "ServiceUUIDs" as 0 "ManufacturerData"
> > > a{sv} 0 "SolicitUUIDs" as 0 "ServiceData" a{sv} 1 "FEAA" ay 18 16 8 3
> > > 117 107 66 97 122 46 103 105 116 104 117 98 46 105 111
> > > "IncludeTxPower" b false
> > >
>
> Using the d-feet application I did a GetAll on the advertisements and
> the data looks identical for both
> Using the new DBus library:
> {'IncludeTxPower': False,
>  'ManufacturerData': {},
>  'ServiceData': {'FEAA': [16,
>                           8,
>                           3,
>                           117,
>                           107,
>                           66,
>                           97,
>                           122,
>                           46,
>                           103,
>                           105,
>                           116,
>                           104,
>                           117,
>                           98,
>                           46,
>                           105,
>                           111]},
>  'ServiceUUIDs': ['FEAA'],
>  'SolicitUUIDs': [],
>  'Type': 'broadcast'}
>
> Using the old Python-dbus library:
> {'IncludeTxPower': False,
>  'ServiceData': {'FEAA': [16,
>                           8,
>                           3,
>                           117,
>                           107,
>                           66,
>                           97,
>                           122,
>                           46,
>                           103,
>                           105,
>                           116,
>                           104,
>                           117,
>                           98,
>                           46,
>                           105,
>                           111]},
>  'ServiceUUIDs': ['FEAA'],
>  'Type': 'broadcast'}
>
> > > $ busctl call ukBaz.bluezero /ukBaz/bluezero/advertisement1
> > > org.freedesktop.DBus.Introspectable Introspect
> > > s "<!DOCTYPE node PUBLIC \"-//freedesktop//DTD D-BUS Object
> > > Introspection 1.0//EN\"\n
> > > \"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd\">\n<!--
> > > GDBus 2.60.4 -->\n<node>\n  <interface
> > > name=\"org.freedesktop.DBus.Properties\">\n    <method name=\"Get\">\n
> > >      <arg type=\"s\" name=\"interface_name\" direction=\"in\"/>\n
> > > <arg type=\"s\" name=\"property_name\" direction=\"in\"/>\n      <arg
> > > type=\"v\" name=\"value\" direction=\"out\"/>\n    </method>\n
> > > <method name=\"GetAll\">\n      <arg type=\"s\"
> > > name=\"interface_name\" direction=\"in\"/>\n      <arg type=\"a{sv}\"
> > > name=\"properties\" direction=\"out\"/>\n    </method>\n    <method
> > > name=\"Set\">\n      <arg type=\"s\" name=\"interface_name\"
> > > direction=\"in\"/>\n      <arg type=\"s\" name=\"property_name\"
> > > direction=\"in\"/>\n      <arg type=\"v\" name=\"value\"
> > > direction=\"in\"/>\n    </method>\n    <signal
> > > name=\"PropertiesChanged\">\n      <arg type=\"s\"
> > > name=\"interface_name\"/>\n      <arg type=\"a{sv}\"
> > > name=\"changed_properties\"/>\n      <arg type=\"as\"
> > > name=\"invalidated_properties\"/>\n    </signal>\n  </interface>\n
> > > <interface name=\"org.freedesktop.DBus.Introspectable\">\n    <method
> > > name=\"Introspect\">\n      <arg type=\"s\" name=\"xml_data\"
> > > direction=\"out\"/>\n    </method>\n  </interface>\n  <interface
> > > name=\"org.freedesktop.DBus.Peer\">\n    <method name=\"Ping\"/>\n
> > > <method name=\"GetMachineId\">\n      <arg type=\"s\"
> > > name=\"machine_uuid\" direction=\"out\"/>\n    </method>\n
> > > </interface>\n  <interface
> > > name=\"org.freedesktop.DBus.ObjectManager\">\n    <method
> > > name=\"GetManagedObjects\">\n      <arg type=\"a{oa{sa{sv}}}\"
> > > name=\"object_paths_interfaces_and_properties\" direction=\"out\">\n
> > >    </arg>\n    </method>\n    <signal name=\"InterfacesAdded\">\n
> > > <arg type=\"o\" name=\"object_path\">\n      </arg>\n      <arg
> > > type=\"a{sa{sv}}\" name=\"interfaces_and_properties\">\n      </arg>\n
> > >    </signal>\n    <signal name=\"InterfacesRemoved\">\n      <arg
> > > type=\"o\" name=\"object_path\">\n      </arg>\n      <arg type=\"as\"
> > > name=\"interfaces\">\n      </arg>\n    </signal>\n  </interface>\n
> > > <interface name=\"org.bluez.LEAdvertisement1\">\n    <annotation
> > > name=\"org.freedesktop.DBus.Properties.PropertiesChanged\"
> > > value=\"const\">\n    </annotation>\n    <method name=\"Release\">\n
> > >    <annotation name=\"org.freedesktop.DBus.Method.NoReply\"
> > > value=\"true\">\n      </annotation>\n    </method>\n    <property
> > > type=\"s\" name=\"Type\" access=\"read\">\n    </property>\n
> > > <property type=\"as\" name=\"ServiceUUIDs\" access=\"read\">\n
> > > </property>\n    <property type=\"a{sv}\" name=\"ManufacturerData\"
> > > access=\"read\">\n    </property>\n    <property type=\"as\"
> > > name=\"SolicitUUIDs\" access=\"read\">\n    </property>\n    <property
> > > type=\"a{sv}\" name=\"ServiceData\" access=\"read\">\n
> > > </property>\n    <property type=\"b\" name=\"IncludeTxPower\"
> > > access=\"read\">\n    </property>\n  </interface>\n</node>\n"
> >
> >
> >
> > --
> > Luiz Augusto von Dentz