[U-Boot] [PATCH v3 01/10] Add getenv_ulong() to read an integer from an environment variable

Simon Glass
2011-10-14T23:27:22Z

Hi Wolfgang,

On Fri, Oct 14, 2011 at 2:42 PM, Wolfgang Denk <wd@denx.de> wrote:
> Dear Simon Glass,
>
> In message <1318626284-11161-1-git-send-email-sjg@chromium.org> you wrote:
>> This is not an uncommon operation in U-Boot, so let's put it in a common
>> function.
>>
>> Signed-off-by: Simon Glass <sjg@chromium.org>
> ...
>> +ulong getenv_ulong(const char *name, int base, ulong default_val)
>> +{
>> + ? ? char buff[20];
>> + ? ? const char *str = NULL;
>> +
>> + ? ? /*
>> + ? ? ?* Prior to the import of the environment into the hashtable we
>> + ? ? ?* should not call getenv()
>> + ? ? ?*/
>> + ? ? if (gd->flags & GD_FLG_ENV_READY)
>> + ? ? ? ? ? ? str = getenv(name);
>> + ? ? else if (getenv_f(name, buff, sizeof(buff)) > 0)
>> + ? ? ? ? ? ? str = buff;
>> + ? ? return str ? simple_strtoul(str, NULL, base) : default_val;
>> +}
>
> Sorry, I just changed my mind.
>
> The issue with using getenv() before relocation is that it uses just a
> tiny buffer (usually 32 bytes) in the global data structure to store
> the result, which is often not sufficient for user provided data (some
> boards have hwconfig strings that are _much_ longer than that, and
> only the caller knows what to expect).
>
> It's only now that I realize that we are dealing with int / long
> values here only, so the length of the expected strings is indeed
> limited - actually the buffer you provide here is way smaller that
> what getenv() uses.
>
> Can we please switch back to the previous version, but insert a
> comment that explains why getenv_f() is not needed in this specific
> case?

OK I have done that and sent version 4 of that patch.

>
> Thanks, and apologies for causing additional efforts.

No problem.

Regards,
Simon

>
> Best regards,
>
> Wolfgang Denk
>
> --
> DENX Software Engineering GmbH, ? ? MD: Wolfgang Denk & Detlev Zundel
> 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
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>