Re: [RFC] Splitting out kernel<=>userspace ABI headers

[Erik Andersen <andersen@codepoet.org>]

On Fri Sep 02, 2005 at 10:53:19PM -0700, H. Peter Anvin wrote:
> Erik Andersen wrote:
> >On Fri Sep 02, 2005 at 10:22:20PM -0700, H. Peter Anvin wrote:
> >
> >>Exportable types need to be double-underscore types, because the header 
> >>files in user space that would include them can generally not include 
> >><stdint.h>.
> >
> >
> >I'm not talking about kernel headers that have to worry about
> >eventually being included in user space headers.  Those nearly
> >all live in include/asm.  I'm talking about the kernel headers
> >that define how userspace is supposed to interface with
> >particular kernel drivers or hardware.  Headers such as
> >linux/cdrom.h and linux/loop.h and linux/fb.h.
> >
> 
> What are you going to do with them if you're not going to include them 
> in userspace?!!!
> 
> If you're proposing one policy for linux/loop.h and one for sys/stat.h, 
> I would have to classify that as insane.  Everything that gets exported 
> to userspace should behave the same way, please.

That is certainly not what I was proposing.  Why are you bringing
sys/stat.h into this?  The contents of sys/stat.h are entirely up
to SUSv3 and the C library to worry about.  Nobody has proposed
mucking with that.  I dunno about your C library, but mine
doesn't include linux/* header files (not even sys/stat.h).  And
I'd really like to fix uClibc to not use any asm/* either, since
much of it is entirely unsuitable for user space.

I am proposing a single consistant policy for all of linux/* such
that all linux/* headers that need integer types of a specific
size shall #include unistd.h and use ISO C99 types rather that
the ad-hoc kernel types they now use.

The policy has _long_ been that user space must never include
linux/* header files.  Since we are now proposing a project to
reverse this policy, the long standing policy making linux/*
verboten now leaves us completely free to do pretty much anything
with linux/*.  And what I want is for linux/* to use the shiny
ISO C99 types.

 -Erik

--
Erik B. Andersen             http://codepoet-consulting.com/
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