Hi Ian, hello Hans!
That's an interesting find, Ian - thank you.
Unfortunately it seems that flagging our environment vars accordingly
isn't enough (on its own) to prevent them from being written by
"saveenv". I've been testing
#define CONFIG_ENV_FLAGS_LIST_STATIC "fel_booted:bo,fel_scriptaddr:xo"
which achieves the desired flags, but doesn't alter saveenv behaviour.
Setting them to read-only ("r" access flag) doesn't help, as it won't
allow the setenv_*() calls to alter the vars in the first place.
As you have observed, this is a more general U-Boot problem - other
'volatile' information might end up in the environment (and saveenv)
as well, e.g. "ipaddr" and "serverip" retrieved by DHCP.
Regards, B. Nortmann
Am 12.09.2015 um 14:24 schrieb Hans de Goede:
Hi,
On 12-09-15 13:58, Ian Campbell wrote:
On Thu, 2015-09-10 at 20:34 +0200, Hans de Goede wrote:
[...]
What if the user interrupts auto-boot with a fel provided boot.scr
and then does "saveenv" ?
This is an interesting question which is more generic than just these
variable, i.e. it applies to some extent to "ipaddr" when someone does
"dhcp ; saveenv" too.
Grepping around to see if there was any special handling for ipaddr I
came across "Vendor Parameter Protection" in the top-level README as
well as "CONFIG_ENV_FLAGS_LIST_DEFAULT" (and _STATIC) and various
default settings in include/env_flags.h.
I think CONFIG_ENV_FLAGS_LIST_* are what we want, and we want fel* to
be flagged "r" for read only
Ah, yes that sounds exactly what we want, thanks for figuring that
out.
and perhaps given an appropriate type
(either "d" or "x" for decimal or hex respectively, I suppose).
Regards,
Hans
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