Re: Using kernel headers that are not for the running kernel

[Jeff Garzik <jgarzik@pobox.com>]

On Sat, Jun 19, 2004 at 05:46:50AM -0500, Rob Landley wrote:
> The linux-kernel maintainers apparently decided that C libraries using kernel 
> headers to actually interface with the kernel was a bad idea.  Apparently, 
> interfacing with the kernel from a C library is not a proper use for kernel 
> headers, or something.  (I tried to follow the logic in this discussion, but 
> never actually found any, despite repeated attempts.  It always seemed to 
> boil down to "can't be bothered", "userspace shouldn't use kernel headers and 
> this includes the C library", etc...)

No, the problem is that the only thing that needs to be shared are the
_ABI_ headers, which are unfortunately mixed in with kernel-internal
headers and definitions.  This leads to use of kernel-internal
definitions in userspace, which leads to breakage.  This also leads to
restrictions on changing -kernel-internal- headers, because some
userspace wanker is complaining.

Kernel-internal headers and definitions should absolutely never be used
in userspace.

H. Peter Anvin has suggested an include/abi which could be shared, and
this seem quite reasonable to me.  However, the monumental task of
separating kernel-internal definitions from ABI definitions still
remains.

	Jeff, really glad the linux-libc-headers guys started his effort