kay.sievers@vrfy.org
f61d732a02
Hmm, Arndt Bergmann sent a patch like this one a few weeks ago and
I want to bring the question back, if we want to handle net device
naming with udev.
With this patch it is actually possible to specify something like this
in udev.rules:
KERNEL="dummy*", SYSFS{address}="00:00:00:00:00:00", SYSFS{features}="0x0", NAME="blind%n"
KERNEL="eth*", SYSFS{address}="00:0d:60:77:30:91", NAME="private"
and you will get:
[root@pim udev.kay]# cat /proc/net/dev
Inter-| Receive | Transmit
face |bytes packets errs drop fifo frame compressed multicast|bytes packets errs drop fifo colls carrier compressed
lo: 1500 30 0 0 0 0 0 0 1500 30 0 0 0 0 0 0
private: 278393 1114 0 0 0 0 0 0 153204 1468 0 0 0 0 0 0
sit0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
blind0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
The udevinfo program is also working:
[root@pim udev.kay]# ./udevinfo -a -p /sys/class/net/private
looking at class device '/sys/class/net/private':
SYSFS{addr_len}="6"
SYSFS{address}="00:0d:60:77:30:91"
SYSFS{broadcast}="ff:ff:ff:ff:ff:ff"
SYSFS{features}="0x3a9"
SYSFS{flags}="0x1003"
SYSFS{ifindex}="2"
SYSFS{iflink}="2"
SYSFS{mtu}="1500"
SYSFS{tx_queue_len}="1000"
SYSFS{type}="1"
follow the class device's "device"
looking at the device chain at '/sys/devices/pci0000:00/0000:00:1e.0/0000:02:01.0':
BUS="pci"
ID="0000:02:01.0"
SYSFS{class}="0x020000"
SYSFS{detach_state}="0"
SYSFS{device}="0x101e"
SYSFS{irq}="11"
SYSFS{subsystem_device}="0x0549"
SYSFS{subsystem_vendor}="0x1014"
SYSFS{vendor}="0x8086"
The matching device will be renamed to the given name. The device name
will not be put into the udev database, cause the kernel renames the
device and the sysfs name disappears.
I like it, cause it plugs in nicely. We have all the naming features
and sysfs queries and walks inside of udev. The sysfs timing races
are already solved and the management tools are working for net devices
too. nameif can only match the MAC address now. udev can match any sysfs
value of the device tree the net device is connected to.
But right, net devices do not have device nodes :)
udev - a userspace implementation of devfs
For more information on the design, and structure of this project, see the
files in the docs/ directory.
To use:
- You must be running a 2.6 version of the Linux kernel.
- Your 2.6 kernel must have had CONFIG_HOTPLUG enabled when it was built.
- Make sure sysfs is mounted. udev will figure out where sysfs is mounted, but
the traditional place for it is at /sys. You can mount it by hand by running:
mount -t sysfs none /sys
- Make sure you have the latest version of the linux-hotplug scripts. They are
available at linux-hotplug.sf.net or from your local kernel.org mirror at:
kernel.org/pub/linux/utils/kernel/hotplug/
They are required in order for udev to work properly.
If for some reason you do not install the hotplug scripts, you must tell the
kernel to point the hotplug binary at wherever you install udev at. This can
be done by:
echo "/sbin/udev" > /proc/sys/kernel/hotplug
- Build the project:
make
Note:
There are a number of different flags that you can use when building
udev. They are as follows:
prefix
set this to the default root that you want udev to be
installed into. This works just like the 'configure --prefix'
script does. Default value is ''. Only override this if you
really know what you are doing.
USE_KLIBC
if set to 'true', udev is built and linked against the
included version of klibc. Default value is 'false'.
USE_LOG
if set to 'true', udev will emit messages to the syslog when
it creates or removes device nodes. This is helpful to see
what udev is doing. This is enabled by default. Note, if you
are building udev against klibc it is recommended that you
disable this option (due to klibc's syslog implementation.)
DEBUG
if set to 'true', debugging messages will be sent to the syslog
as udev is run. Default value is 'false'.
KERNEL_DIR
If this is not set it will default to /lib/modules/`uname -r`/build
This is used if USE_KLIBC=true to find the kernel include
directory that klibc needs to build against. This must be set
if you are not building udev while running a 2.6 kernel.
So, if you want to build udev using klibc with debugging messages, you
would do:
make USE_KLIBC=true DEBUG=true
- Install the project:
make install
This will put the udev binary in /sbin, create the /udev and /etc/udev
directories, and place the udev configuration files in /etc/udev. You
will probably want to edit the namedev.* files to create custom naming
rules. More info on how the config files are set up are contained in
comments in the files, and is located in the documentation.
- Add and remove devices from the system and marvel as nodes are created
and removed in /udev/ based on the device types.
- If you later get sick of it, uninstall it:
make uninstall
Things are still quite rough, but it should work properly. If nothing
seems to happen, make sure your build worked properly by running the
udev-test.pl script as root in the test/ subdirectory of the udev source
tree.
Development and documentation help is very much appreciated, see the TODO
file for a list of things left to be done.
Any comment/questions/concerns please let me and the other udev developers
know by sending a message to the linux-hotplug-devel mailing list at:
linux-hotplug-devel@lists.sourceforge.net
greg k-h
greg@kroah.com