Udev nitpicks

Kevin P. Fleming kpfleming at linuxfromscratch.org
Fri Jun 25 07:13:15 PDT 2004

Alexander E. Patrakov wrote:

> 1)
> Udev installs its default "permissions" and "rules" files as 
> 50-udev.{permissions,rules}. This is bad:
> The permissions specified in 50-udev.permissions are inappropriate for 
> LFS, because the "uucp" group doesn't exist and the "500" gid for the 
> camera may be (and is actually on my system) used for some purpose. 
> Proposed solution: remove this 50-udev.permissions file after udev 
> installation.
> The rules specified in 50-udev.rules are bad duplicates of the rules 
> provided by LFS. Proposed solution: either remove 50-udev.rules after 
> installation (preferred) or remove duplicate entries from 00-lfs.rules

Why is any of this important? The whole point of providing our own rules 
file is to override the parts of the stock file that we want to change, 
without actually having to change that file (as we used to do). udev 
supports this just fine, duplicate rules in the 50-udev.rules file are 
ignored. Using this technique is the documented way to use udev, and it 
ensures that if the user upgrades udev later they don't have to re-run 
our "modify the 50-udev.rules" file at all. In fact, we don't even have 
to rename the default rules file, because 00-lfs.rules sorts before 
udev.rules anyway, so our patch could even just leave the default files 

If you want to have the user use _only_ LFS provided rules and 
permissions files, then you've got to ensure that they will always 
follow those same steps in the future when the upgrade udev, and the LFS 
team will need to continue to provide updated rules and permissions 
files to keep pace with the default files as they offer new entries for 
people to use. Do you really want to have to do that?

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