svn commit: r300718 - in head/sys: kern sys

[Hans Petter Selasky]

On 05/27/16 00:54, Ian Lepore wrote:
> On Thu, 2016-05-26 at 14:37 -0700, Gleb Smirnoff wrote:
>>   Hans,
>>
>> On Thu, May 26, 2016 at 08:41:55AM +0000, Hans Petter Selasky wrote:
>> H> Author: hselasky
>> H> Date: Thu May 26 08:41:55 2016
>> H> New Revision: 300718
>> H> URL: https://svnweb.freebsd.org/changeset/base/300718
>> H>
>> H> Log:
>> H>   Add support for boolean sysctl's.
>> H>
>> H>   Because the size of bool can be implementation defined, make a
>> bool
>> H>   sysctl handler which handle bools. Userspace sees the bools like
>> H>   unsigned 8-bit integers. Values are filtered to either 1 or 0
>> upon
>> H>   read and write, similar to what a compiler would do.
>> H>
>> H>   Requested by:	kmacy @
>> H>   Sponsored by:	Mellanox Technologies
>>
>> Would be nice if sysctl(8) would explicitly display them as "true" or
>> "false"
>> instead of 0 and 1. Now the userland can't differ them from uint8_t
>> oids.
>
> If it displayed them that way, then users would want to set them using
> the true/false strings too.  If you start down that path you eventually
> end up adding support for 0/1/true/false/yes/no/on/off, and if you
> don't do that in exactly once place you end up with some oids accepting
> all the values and others accepting only some of them, and the user
> experience is confusing at best.
>

Hi,

My initial thought was that bool support should be in the kernel only, 
because sizeof(bool) varies. So it is not directly compatible to 
userspace. Even though we might not support true/false/on/off strings, 
do you think bool is worth it's own CTL type, which falls back to 
CTLTYPE_U8 ?

--HPS