required/suggested devfs userland tool functionality

Matthew Dillon dillon at apollo.backplane.com
Mon Jul 6 10:00:41 PDT 2009


:But do you really want to perform regexp/glob matching in the kernel?  Or 
:do you want to restrict the users to prefix matching?

   Yes, it is not a problem.  It is not a critical path.  But not Regex.
   Just simple ?/* wildcarding.  Regex is overrated and unnecessarily
   complex for what we want to accomplish.

:I think we basically need to deal with multiple things here:
:
:1. no race conditions when creating device nodes

    I think Alex's locks will deal with that case.

:2. give the user enough flexibility
:3. allow the user to use chmod/chown?

    Yes, absolutely.  Those are important functions and there is no reason
    not to allow them.  The initial permissions and ownership can be set
    based on the rule set, and changed thereafter by userland.

:I don't have an opinion yet what is better, but maybe we should assess 
:which kind of rules a user is expected to write (which rules do we want to 
:ship per default?), and then we can decide whether it is worthwhile to put 
:the rules management in the kernel, or whether it better goes into userland.
:
:cheers
:   simon

    I'd expect something simple like:

	da*		640	root	operator

    And even a short-cut by classification so we don't have to list
    every disk driver under the sun:

	D_DISK		640	root	operator

						-Matt






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