kern/59374: KERNEL_DIR: support passing directories from 'boot'

[Thomas Klausner <wiz%NetBSD.org@localhost>]

>Number:         59374
>Category:       kern
>Synopsis:       KERNEL_DIR: support passing directories from 'boot'
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Mon Apr 28 14:50:00 +0000 2025
>Originator:     Thomas Klausner
>Release:        NetBSD 10.99.14
>Organization:

>Environment:
	
	
Architecture: x86_64
Machine: amd64
>Description:
With the new KERNEL_DIR option, you can install kernel and modules together
into /netbsd, i.e.

/netbsd/kernel
/netbsd/kernel.gdb
/netbsd/modules/module_name/module_name.kmod

The updated boot code looks for /netbsd/kernel, /onetbsd/kernel, /netbsd.old/kernel
instead of /netbsd, /onetbsd, /netbsd.old.

However, when you manually want to boot a particular kernel, the
commandline in 'boot' has changed from

boot netbsd.test

to

boot netbsd.test/kernel

I'd like the following change:

When 'boot' finds that a path passed on the command line is a
directory, it automatically adds '/kernel' itself.

This way, the UI of the 'boot' command line doesn't change and admins don't need
to remember if they are on a KERNEL_DIR system or not.
>How-To-Repeat:
n/a
>Fix:
Please.

>Unformatted: