[RFC PATCH] tools: env: Add an option to have an empty default environment

[Wolfgang Denk]

Dear Chris Packham,

In message <20200813013727.8186-1-judge.packham at gmail.com> you wrote:
> When building envtools via tools-only_defconfig the builtin defaults
> are based on options in the defconfig. For example:
>
>   bootcmd=bootp; setenv bootargs root=/dev/nfs nfsroot=${serverip}:${rootpath} ip=${ipaddr}:${serverip}:${gatewayip}:${netmask}:${hostname}::off; bootm
>   bootdelay=2
>   baudrate=115200
>   stdin=serial,cros-ec-keyb,usbkbd
>   stdout=serial,vidconsole
>   stderr=serial,vidconsole
>   ethaddr=00:00:11:22:33:44
>   eth3addr=00:00:11:22:33:45
>   eth5addr=00:00:11:22:33:46
>   eth6addr=00:00:11:22:33:47

Having any specific MAC addresses set in the default environment has
always been a strict No-Go as it is just begging for trouble.

If this was a real example, that code should be fixed!!

> These may or may not be sensible for any particular target. Rather than
> trying to have a set of defaults that work for every target add a config
> option to make the default environment completely empty.

An empty default environment is even worse, as you are missing vital
settings like baudrate, bootdelay etc.  There are good chances to
brick your board with such settings.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
The word "fit", as I understand it, means "appropriate to a purpose",
and I would say the body of the Dean is supremely appropriate to  the
purpose of sitting around all day and eating big heavy meals.
                                 - Terry Pratchett, _Moving Pictures_