Re: user_memcpy()

On Fri, 29 Apr 2005, Axel Dörfler wrote:

> François Revol made me recognize a design flaw in our user_memcpy()/
> user_strlcpy() API: you have to check the validity of the user address
> yourself, ie. you have to make sure it's in user space.
> But we don't have a function for this, just the (kernel private) macro
> IS_USER_ADDRESS().
>
> And while I like to keep the macro, we should at least export an
> is_user_address() function.
>
> But that would still open a possible source of errors - as you still
> have to check the address yourself. François suggested to do something
> similar than Linux that has copy_to_user() and copy_from_user()
> functions.
> Since we also have a user_strlcpy() function, I would suggest the
> following:
> 	copy_to_user()
> 	copy_from_user()
> 	strlcpy_to_user()
> 	strlcpy_from_user()
> 	user_memset() - or memset_user()?
>
> Any preferences?

Sounds good, save that I would probably call the first two 
memcpy_{from,to}_user(). I wonder if we might also want to have versions 
that copy between user addresses.

CU, Ingo