Re: CEPH_RBD_API: options on image create

[Jason Dillaman <dillaman@redhat.com>]

> > I am concerned about passing a void* + length to specify the option
> > value since you really can't protect against the user providing data
> > in the incorrect format.  For example, if the backend treated
> > RBD_OPTION_STRIPE_UNIT as a 4byte int, what happens if someone
> > passes a 2- or 8-byte int or a 4-byte char* string?
> 
> Then rbd_image_options_set() will fail with EINVAL, because the option
> type (size) is a part of interface.
> 
> I do this by analogy to setsockopt(2):
> 
> http://pubs.opengroup.org/onlinepubs/009695399/functions/setsockopt.html
> 
> Note option type documented for every option there, and it works
> fairly well.
> 
> Following a common practice is an additional argument to this
> approach to me.

Except for the following cases:

sizeof(char*) == sizeof(uint32_t) (32bit)
sizeof(char*) == sizeof(uint64_t) (64bit)

-- 

Jason Dillaman