conf/163508: [rc.subr] [patch] Add " enable" and " disable" commands to rc.subr

[Maxim Ignatenko]

On 26 December 2011 08:12, Doug Barton <dougb at freebsd.org> wrote:
> On 12/24/2011 15:08, Warner Losh wrote:
>>
>> On Dec 24, 2011, at 2:50 PM, Doug Barton wrote:
>>
>>> On 12/24/2011 08:46, Warner Losh wrote:
>>>> Also, let's not reject  it before it is done.  Let's reject it
>>>> when it actually doesn't handle the cases that are interesting.
>>>> No sense in cutting off a good feature because of some
>>>> theoretical problem.  It is a problem we have sometimes in the
>>>> project...
>>>
>>> Warner,
>>>
>>> You seemed to have missed the bit where I said, "We've already been
>>> down this path once before, and it turns out to be way harder to do
>>> this right than it looks at first glance."
>>
>> No, I get that totally.  I just don't care.  The fact that others
>> have failed shouldn't mean we should discourage others from trying.
>> We shouldn't be shooting arrows at people before they are given a
>> chance to produce something good or bad, or when they do shooting
>> them without evaluating their work.
>
> You do get that the OP included a patch, right?
>
>>> Just as an example of potential problems, imagine a scenario where
>>> the user has foo_enable=NO in rc.conf, but the service keeps
>>> starting up anyway.
>>
>> Most people call that a bug, or at least POLA.  The few cases in the
>> tree where bar_enable=yes forces foo_enable=yes can be dealt with.
>
> No, you seem to be missing my point. Because of the way that rc.d
> processes the various *conf* options the last match "wins." So let's say
> that you had foo_enable=0 in /etc/rc.conf; but one of the conf files
> that's processed later has foo_enable=1. If that's the last match, it
> gets started. This is one of the many concerns regarding trying to
> automatically enable or disable things.
>

Proposed patch searches all files (except /etc/defaults/rc.conf) that
are included by load_rc_config() in _reverse_ order, so even if there
are some other files included in rc.conf, foo_enable=NO gets added to
the end of last processed file and we still have foo enabled.