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From: "Peter A. Bigot" <pab@pabigot.com>
To: linux-bluetooth@vger.kernel.org
Subject: how to cleanly shutdown an application using HCI_CHANNEL_USER
Date: Tue, 17 Aug 2021 15:07:17 -0700	[thread overview]
Message-ID: <e17b2044-62cb-cbf7-64b8-c647aa7f6ee7@pabigot.com> (raw)

I'm using an AF_BLUETOOTH socket bound with HCI_CHANNEL_USER from a
user-mode application with cap_net_admin=ep.  As expected this
requires the device be down, and brings the device up automatically.

When I close that socket and exit the application, the device appears
to remain up forever.  Which prevents me from re-starting the
application.

I tried to issue HCIDEVDOWN before closing, but that produces EBADFD
because ioctls cannot be performed with HCI_CHANNEL_RAW.

I can bring the interface down from within the application if, after
closing the socket, I wait a second or so, then create a new bound
HCI_CHANNEL_RAW socket and issue HCIDEVDOWN on it.

Is there some other way to cleanly shut down an application that used
HCI_CHANNEL_USER so that the device is returned to down state on exit?
Or is this supposed to happen automatically (I see code that suggests
it should)?

Kernel version is 5.11.0-7620-generic (System76), and I'm using go
1.16, if that's relevant.

Thanks!

Peter

             reply	other threads:[~2021-08-17 22:07 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-17 22:07 Peter A. Bigot [this message]
2021-08-19 15:01 ` how to cleanly shutdown an application using HCI_CHANNEL_USER Marcel Holtmann
2021-08-19 17:51   ` Luiz Augusto von Dentz
2021-08-23 20:32   ` Tedd Ho-Jeong An

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