[Dev] Removable block devices in TIZEN

Jacek Pielaszkiewicz j.pielaszkie at samsung.com
Wed Oct 9 07:52:49 GMT 2013


> -----Original Message-----
> From: Rusty Lynch [mailto:rusty.lynch at intel.com]
> Sent: Tuesday, October 08, 2013 6:12 PM
> To: Jacek Pielaszkiewicz
> Cc: dev at lists.tizen.org
> Subject: Re: [Dev] Removable block devices in TIZEN
> 
> On Tue, 2013-10-08 at 14:59 +0200, Jacek Pielaszkiewicz wrote:
> > Dear all,
> >
> > 	I have created set of patches to implement udisks on TIZEN and
> > replace removable block devices support in system-server by udisk.
> > Main reason for the proposed changes is to implement in TIZEN common
> > and well known functionalities that handle removable devices.
> >
> > 	Implemented changes:
> >
> > (1) System-server patch - remove support for block devices in
> > system-server removal - remove udev rules that triggers action in
> > system-server (rules for add/remove kernel events)
> >
> > (2) Udisks - initial version of the udisks repository for TIZEN -
> > version
> > 2.1.2
> >
> > (3) libatasmart - initial version of the libatasmart repository for
> > TIZEN - version 0.19. The library is required by udisks.
> >
> > (4) udisks-agent - my implementation of an simple agent that works in
> > user space. It handles events triggered by the udisks (add/remove
> > device). The agent provide very basic functionality - mount/unmount
> > removable block device. Any notification is not send to end-user. The
> > agent in assumption should be base for future works and closer
> > integration with rest of TIZEN components. To avoid any security
> issue
> > I added wide rules in polkit to allow every user mount removable
> block devices.
> >
> > (5) polkit patch - add support in the polkit demon to be started by
> systemd.
> > The polkit is required by udisks.
> >
> 
> I think this is the correct direction.  We have no need to handle this
> fundamentally different then most other Linux instances out there.
> 
> >
> > 	Issues/topics that required future works:
> >
> > (1) Multi user support (open topic for TIZEN 3.0)
> >
> > (2) Which API should we exposed for TIZEN applications - native udisk
> > API (dbus based) or build a new one on top of udisk API.
> 
> Lets not create another abstraction layer.  Native apps can just
> directly call into the existing dbus API and web apps do not have
> direct access to arbitrary storage.
> 
> > (3) In version 2.1.2 udisks has limited support for encrypted block
> > devices (only setup and mount such devices). Should we add support
> for
> > other operations like: initial encrypted block devices setup, in
> place
> > encryption/decryption, etc?
> 
> Does the Tizen 2.2 phone already support such things?
It doesn’t,  but such functionalities is available for example in Android. 
End-user can encrypt/decrypt removable block device.

> 
> > (4) Mount points location - by default udisks mount new block devices
> > in /run/media/__user__/__device_name__ in TIZEN it is
> > /opt/storage/sdcard - hardcoded.
> 
> I think we should stop using the oddball location under
> /opt/storage/sdcard and just fix whatever middleware is working under
> this hard coded assumption.
> 
> > (5) Integration udisks with TIZEN security (security-server, ...)
> 
> Last I heard the security-server was marked for death, i.e. the overall
> system was being addressed such that we should not need such a beast
> anymore.  But... I'll let the security folks comment on that.
> 

--
Jacek Pielaszkiewicz
Samsung R&D Institute Poland
Samsung Electronics
Email: j.pielaszkie at samsung.com




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