[ANNOUNCE] udev 136 release

[ANNOUNCE] udev 136 release

[Kay Sievers]

Here comes a new udev version. Thanks to all who have contributed to
this release.

The tarball can be found here:
 ftp://ftp.kernel.org/pub/linux/utils/kernel/hotplug/

The development repository can be found here:
 http://www.kernel.org/git/?p=linux/hotplug/udev.git;a=summary

The ChangeLog can be found here:
 http://www.kernel.org/git/?p=linux/hotplug/udev.git;a=blob;hb=HEAD;f=ChangeLog

udev 136
====
Bugfixes.

We are currently merging the Ubuntu rules in the udev default rules,
and get one step closer to provide a common Linux /dev setup, regarding
device names, symlinks, and default device permissions. On udev startup,
we now expect the following groups to be resolvable to their ids with
glibc's getgrnam():
  disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem.
LDAP setups need to make sure, that these groups are always resolvable at
bootup, with only the rootfs mounted, and without network access available.

Some systems may need to add some new, currently not used groups, or need
to add some users to new groups, but the cost of this change is minimal,
compared to the pain the current, rather random, differences between the
various distributions cause for upstream projects and third-party vendors.

In general, "normal" users who log into a machine should never be a member
of any such group, but the device-access should be managed by dynamic ACLs,
which get added and removed for the specific users on login/logout and
session activity/inactivity. These groups are only provided for custom setups,
and mainly system services, to allow proper privilege separation.
A video-streaming daemon uid would be a member of "audio" and "video", to get
access to the sound and video devices, but no "normal" user should ever belong
to the "audio" group, because he could listen to the built-in microphone with
any ssh-session established from the other side of the world.

/dev/serial/by-{id,path}/ now contains links for ttyUSB devices,
which do not depend on the kernel device name. As usual, unique
devices - only a single one per product connected, or a real
USB serial number in the device - are always found with the same
name in the by-id/ directory.
Completely identical devices may overwrite their names in by-id/
and can only be found reliably in the by-path/ directory. Devices
specified by by-path/ must not change their connection, like the
USB port number they are plugged in, to keep their name.

To support some advanced features, Linux 2.6.22 is the oldest supported
version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
supported. Older kernels should still work, and devices nodes should be
reliably created, but some rules and libudev will not work correctly because
the old kernels do not provide the expected information or interfaces.

Re: [ANNOUNCE] udev 136 release

[Marco d'Itri]

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On Jan 07, Kay Sievers <kay.sievers@vrfy.org> wrote:

> To support some advanced features, Linux 2.6.22 is the oldest supported
> version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
> supported. Older kernels should still work, and devices nodes should be
> reliably created, but some rules and libudev will not work correctly because
> the old kernels do not provide the expected information or interfaces.
Knowing that something unspecified may or may not work is not really
helpful.

-- 
ciao,
Marco

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Re: [ANNOUNCE] udev 136 release

[Kay Sievers]

On Wed, Jan 7, 2009 at 15:34, Marco d'Itri <md@linux.it> wrote:
> On Jan 07, Kay Sievers <kay.sievers@vrfy.org> wrote:
>
>> To support some advanced features, Linux 2.6.22 is the oldest supported
>> version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
>> supported. Older kernels should still work, and devices nodes should be
>> reliably created, but some rules and libudev will not work correctly because
>> the old kernels do not provide the expected information or interfaces.
> Knowing that something unspecified may or may not work is not really
> helpful.

We don't know exactly what may fail, nobody tests almost two years old
kernels with a new udev. That's why we mention that such old kernels
should not be used. The basic operations should still be fine that old
stuff.

Stuff that is known not to work are the device-mapper and md rules,
cdrom_id properties, media change events, matches on DEVTYPE,
libudev's functions to retrieve properties, things that need the
"uevent" file.

The current rules use all that, it will not work correctly, and we
mark it as unsupported. That's all.

Kay