Hi Joe!
Thanks for chiming in, especially seeing that you have previously worked on something very similar.
Am 27.11.2016 um 19:53 schrieb Joe Hershberger:
On Wed, Nov 16, 2016 at 4:29 AM, Bernhard Nortmann bernhard.nortmann@web.de wrote:
"transient" (='t') is like "any", but requests that a variable should not be exported (ENV_FLAGS_VARACCESS_PREVENT_EXPORT).
"system" (='S') is meant for 'internal' variables that
The flags are positional, so 's' is not in use. It seems it would be cleaner to use a lower-case 's'.
You're probably right. I think back then I deliberately picked 'S' to avoid potential confusion (e.g. users specifying "s" when they actuall mean/want "ss"), as trying to set flags to just "S" would result in an error message.
For precisely that reason I'd actually prefer to find letter(s) that would not conflict with existing type or access flags, but 'v'olatile seemed ambiguous / too broad at that time.
[...]
I'm not sure why you are adding "transient" or "volatile" to the varaccess. It is an orthogonal property of a variable. This is obvious from the fact that you need to add yet another to compose varaccess with varlifetime (or something).
I worked on something similar years ago, but never posted an RFC.
That's a very good point. This 'orthogonality' is what actually caused me to come up with that "transient" vs. "system" idea. I think I got misled by the way that U-Boot already combined various "access" bit flags, and it never occured to me to introduce another property with a third flag character. Actually "?av" (any-access, volatile) and "?rv" (read-only, volatile) would represent my intent perfectly well.
I also like your "auto-volatile" concept a lot (i.e. resetting the volatile nature on setenv by the user). To stay unambiguous ('a' = "any" access), maybe this could be tagged 't'emporary. We'd also need a default letter for the lifesspan flag, possibly 'n'ormal?
The temporary (= auto-volatile) flag would also nicely save use from the need to have users fumble with "setenv .flags", and the quirks involved.
Implementing this means some refactoring / a major overhaul of this RFC series, but I think it could be well worth that. I'll definitely give it a try when I find some time.
Regards, B. Nortmann