Re: [PATCH BlueZ 3/4] Link to udev only when needed

From: Antonio Ospite <ospite@studenti.unina.it>
To: Marcel Holtmann <marcel@holtmann.org>
Cc: linux-bluetooth@vger.kernel.org,
	Bastien Nocera <hadess@hadess.net>,
	linux-input@vger.kernel.org, Jim Paris <jim@jtan.com>,
	Ranulf Doswell <ralf@ranulf.net>,
	"Pascal A . Brisset" <pascal44973@pabr.org>,
	Marcin Tolysz <tolysz@gmail.com>,
	Christian Birchinger <joker@netswarm.net>,
	Filipe Lopes <falktx@gmail.com>, Alan Ott <alan@signal11.us>,
	Mikko Virkkila <virkkila@kapsi.fi>,
	Simon Wood <simon@mungewell.org>, Arc Riley <arcriley@gmail.com>
Subject: Re: [PATCH BlueZ 3/4] Link to udev only when needed
Date: Thu, 25 Aug 2011 16:14:54 +0200	[thread overview]
Message-ID: <20110825161454.45a0b27998f577a737a2e579@studenti.unina.it> (raw)
In-Reply-To: <20110819210854.81dff694ad455da3ed0e6e96@studenti.unina.it>

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On Fri, 19 Aug 2011 21:08:54 +0200
Antonio Ospite <ospite@studenti.unina.it> wrote:

> On Fri, 19 Aug 2011 10:58:02 +0200
> Antonio Ospite <ospite@studenti.unina.it> wrote:
> 
> > On Thu, 18 Aug 2011 16:18:57 -0700
> > Marcel Holtmann <marcel@holtmann.org> wrote:
> > 
> [...]
> > > 
> > > I rather have the Sixaxis plugin being an external plugin only then. So
> > > you are not allowed to make this builtin.
> > > 
> > 
> > Marcel, I guess that an _external_ plugin in BlueZ context is one which
> > is not embedded in the bluetoothd binary but rather distributed as a
> > shared object, isn't it? Are there examples of such a plugin in bluez
> > tree I can copy from?
> >
> 
> OK, I think I've got it, it is external-dummy, this is how I did it:
> 
> ---
>  Makefile.am |   10 ++++++----
>  1 files changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/Makefile.am b/Makefile.am
> index 4bcff4d..ff33bf0 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -230,8 +230,10 @@ builtin_sources += thermometer/main.c \
>  endif
>  
>  if SIXAXISPLUGIN
> -builtin_modules += sixaxis
> -builtin_sources += plugins/sixaxis.c
> +plugin_LTLIBRARIES += plugins/sixaxis.la
> +plugins_sixaxis_la_SOURCES = plugins/sixaxis.c
> +plugins_sixaxis_la_LDFLAGS = -module -avoid-version -no-undefined @UDEV_LIBS@
> +plugins_sixaxis_la_CFLAGS = -fvisibility=hidden @DBUS_CFLAGS@ @GLIB_CFLAGS@ @UDEV_CFLAGS@
>  endif
> 

This is not enough, the external plugin can be compiled but I can be used
at runtime because it is using functions from src/storage.c and others,
which seem to be embedded inside bluetoothd only, so I get:

bluetoothd[23459]: Can't load plugin \
  /home/ao2/Proj/PS3/PS3_sixaxis/bluez/plugins/.libs/playstation-peripheral.so: \
  /home/ao2/Proj/PS3/PS3_sixaxis/bluez/plugins/.libs/playstation-peripheral.so: \
  undefined symbol: write_device_name

I could link the needed object files like storage.o and company into the
plugin binary, but definitely this doesn't look OK. Should a shared library
provide those "utility" functions to bluetoothd _and_ external plugins?

This plugin is the first non-trivial external plugin I can see in the tree,
so maybe this problem has never showed up before.

Thanks,
   Antonio

-- 
Antonio Ospite
http://ao2.it

PGP public key ID: 0x4553B001

A: Because it messes up the order in which people normally read text.
   See http://en.wikipedia.org/wiki/Posting_style
Q: Why is top-posting such a bad thing?

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