Re: ldap_get_values() called on binary data - does this return an error, or garbage data?

On 03 Apr 2024, at 13:03, Ond=C5=99ej Kuzn=C3=ADk <[email protected]> =
wrote:

>> This has been historically vague - first off, what happens if an
>> attempt is made to call ldap_get_values() on binary data, do you get
>> an error, or garbage data? The source isn't giving me a clear answer.
>=20
> Hi Graham,
> in this case binary data means embedded NULs (\0) can be found: given
> that what you get back is a naive char * for each value, you stand to
> lose information about whether that NUL is part of the value or a
> string terminator.

So that means garbage data is returned.

>> Second question is how do you know which of ldap_get_values() or
>> ldap_get_values_len() to call? Obviously you can manually know this,
>> but I'm interested in automated behaviour. What is the canonical way
>> to discover that if you queried a jpegPhoto (for example) that the
>> result would be binary?
>=20
> You either expect the data to be a string of some sort (no embedded
> NULs), then you're free to use whichever or you are prepared to accept
> arbitrary bytestreams and you need to use the one that returns =
bervals.
> That's all there is.

So am I right in understanding there is no way to ask the server "what =
type is this attribute you just gave me, is this arbitrary octets or a =
NUL terminated string"?

> You're welcome to propose better wording if you can make it clearer to =
a
> reasonably competent C developer (I'm sure we can assume that they
> understand how strings are laid out etc.)

The reason this matters has nothing to do with reasonably competent C =
developers, but rather options given to end users.

If the end user is allowed to provide an attribute in a configuration =
file, do I force the end user to know about binary values (as is common =
now), or is there a way I can be nice to the end user and have the =
system behave sensibly based on whether the return data is a string or =
binary?

Regards,
Graham
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