Re: Problem parsing %s in udev rules

[Greg KH <greg@kroah.com>]

On Tue, Oct 12, 2004 at 05:04:21PM -0600, Andrew Patterson wrote:
> Kay,
> 
> On Thu, 2004-10-07 at 02:30 +0200, Kay Sievers wrote:
> > On Wed, Oct 06, 2004 at 06:23:05PM -0600, Andrew Patterson wrote:
> > > On Thu, 2004-10-07 at 01:50 +0200, Kay Sievers wrote:
> > > > On Wed, Oct 06, 2004 at 05:33:04PM -0600, Andrew Patterson wrote:
> > > > > Udev seems to be chopping off anything seen in a rule after a %s.  For
> > > > > example, if I have the following rule:
> > > > > 
> > > > > BUS="scsi", KERNEL="sd*", PROGRAM="/sbin/scsi_id", NAME="%k",
> > > > > SYMLINK="scsi_disks/some-proceeding-stuff-%s{model}-some-following-
> > > > > stuff"
> > > > > 
> > > > > Everything after the %s{model} is ignored.
> > > > > 
> > > > > Furthermore, everything in model following whitespace is ignored as
> > > > > well.  I.e, if model contains "HP 34.7G", the resulting device file
> > > > > created is /dev/scsi_disks/some-proceeding-stuff-HP.
> > > > > 
> > > > > I used the following command to run this test:
> > > > > 
> > > > > # DEVPATH=/block/sda ACTION­d ./udev block
> > > > > 
> > > > > I also get the same behavior when using udevstart (patched to fix
> > > > > parameter passing problems).
> > > > 
> > > > If your sysfs value contains spaces, which is the delimiter for multiple
> > > > symlinks, it will not work.
> > > > 
> > > > udev can't do this now, you need to wrap the call with an external script,
> > > > which ensures sane values.
> > > > 
> > > 
> > > That explains the spaces.  What about stuff trailing %s, if %s does not
> > > contain spaces.  I.e, in the above example, model is ST336753LC and the
> > > resulting device file is /dev/scsi_disks/some-proceding-stuff-
> > > ST336753LC.
> > 
> > I expect the model value has trailing spaces.
> > 
> > You may look with:
> >   udevinfo -a -p /block/sdX
> 
> Yes it does, and it seems for most SCSI devices, vendor and model will
> have trailing spaces.

It all depends on the vendor and model :)

> I have included a patch to udev-036 to deal with
> this issue.  It trims off trailing whitespace for all sysfs attributes.
> It might be better to trim off leading whitespace as well.  

We already trim it off when matching, but we also allow matching if you
do put the spaces in there.  This patch breaks that, right?

> I also wonder if it might be a good idea to do some sort of
> transformation for characters in an attribute that are illegal in a file
> system, rather than just chopping everything off. e.g, spaces that are
> not leading or trailing would be changed to underscores.

ick, no.

thanks,

greg k-h


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