kern/60874: auto-assign devfs ruleset numbers

[Colin Percival]

>Number:         60874
>Category:       kern
>Synopsis:       auto-assign devfs ruleset numbers
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          change-request
>Submitter-Id:   current-users
>Arrival-Date:   Sat Jan 03 14:30:11 PST 2004
>Closed-Date:
>Last-Modified:
>Originator:     Colin Percival
>Release:        FreeBSD 5.2-RC i386
>Organization:
>Environment:
System: FreeBSD fafnir.daemonology.net 5.2-RC FreeBSD 5.2-RC #2: Fri Jan 2 17:59:36 GMT 2004 cperciva at fafnir.daemonology.net:/usr/obj/usr/src/sys/GENERIC i386

>Description:

At present, devfs ruleset numbers must be specified.  This could cause 
problems with software which creates jails (with associated /dev mounts)
since two different applications might overwrite each other's rulesets.

It would be nice if devfs(8) and the associated kernel code had an
option for assigning an unused ruleset -- eg, 'devfs -m /foo/dev ruleset -1'
would result in the kernel finding an unused ruleset number in a given 
range (32-63, perhaps?) and assigning that ruleset number to the devfs.

>How-To-Repeat:
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted: