On Wed, Dec 31, 2003 at 11:24:53AM -0800, Greg KH wrote:
> > There should be a possibility to tell udev not to create a device node.
> >
> > device-mapper: Usually set up by libdevmapper (or EVMS tools) which
> > creates the device node on its own under /dev/mapper/<name>.
> >
> > With udev a second device is created named /dev/dm-<minor> which is not
> > really needed.
>
> Good point. Ok, I'll agree with you. Care to make up a patch for this
> kind of feature?
Yes, I can try.
There was no way to tell not to do anything so I created one. Errors
are signalled via negative return values, so I thought that a positive,
non-zero one could mean to ignore the device. I don't like it but
perhaps you have a better solution.
This one is nothing important, just add some quotes to be more consistent
with the rest and make sure that the return value is positive (since the
error return values are negative). Hmm?
Here is a slightly better version that prints the usage if a unknown option is given:
kay@pim:~/src/udev.kay$ ./udev -x
./udev: invalid option -- x
Usage: [-qrVh]
-q arg query database
-r print udev root
-V print udev version
-h print this help text
> Here is a patch that makes it possible to call udev with options on the command line.
> Valid options are for now:
>
> -V for the udev version:
> kay@pim:~/src/udev.kay$ ./udev -V
> udev, version 011_bk
>
> -r for the udev root:
> kay@pim:~/src/udev.kay$ ./udev -r
> /udev/
>
> -q to query the database with the sysfs path for the name of the node:
> kay@pim:~/src/udev.kay$ ./udev -q /class/video4linux/video0
> test/video/webcam0
Attached is a patch against udev-008 to send out a D-BUS message when a
device node is added or removed.
Using D-BUS lingo, udev acquires the org.kernel.udev service and sends
out a NodeCreated or NodeDeleted signal on the
org.kernel.udev.NodeMonitor interface. Each signal carries two
parameters: the node in question and the corresponding sysfs path.
[Note: the D-BUS concepts of service, interface, object can be a bit
confusing at first glance]
An example program listening for these messages looks like this
#!/usr/bin/python
import dbus
import gtk
def udev_signal_received(dbus_iface, member, service, object_path, message):
[filename, sysfs_path] = message.get_args_list()
if member=='NodeCreated':
print 'Node %s created for %s'%(filename, sysfs_path)
elif member=='NodeDeleted':
print 'Node %s deleted for %s'%(filename, sysfs_path)
def main():
bus = dbus.Bus(dbus.Bus.TYPE_SYSTEM)
bus.add_signal_receiver(udev_signal_received,
'org.kernel.udev.NodeMonitor', # interface
'org.kernel.udev', # service
'/org/kernel/udev/NodeMonitor') # object
gtk.mainloop()
if __name__ == '__main__':
main()
and this is the output when hot-plugging some usb-storage.
[david@laptop udev-008]$ ~/node_monitor.py
Node /udev/sda created for /block/sda
Node /udev/sda1 created for /block/sda/sda1
Node /udev/sda1 deleted for /block/sda/sda1
Node /udev/sda deleted for /block/sda
The patch requires D-BUS 0.20 or later while the python example program
requires D-BUS from CVS as I only recently applied a patch against the
python bindings.
the older udev.config file is now called udev.rules.
This allows us to better control configuration values, and move away from
the environment variables.
This patch adds a callout config type to udev, so external programs can be
called to get serial numbers or id's that are not available as a sysfs
attribute.
This patch:
1) removes the three database files for just one udevdb.tdb file.
2) adds udevdb_init() and udevdb_exit() functions
3) initializes database now in main() in udev.c.
Please look it over.
