Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.

Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.

[Ihar 'Philips' Filipau]

Jeff Garzik wrote:
>>hpa IIRC suggested to create a separate directory:
>>include/abi
>>and then all relevant parts of the kernel should publish their public
>>interface in the abi directory. Would that be usefull?
> 
> 
> I support include/abi, or some other directory that segregates
> user<->kernel shared headers away from kernel-private headers.
> 
> I don't see how that would be auto-generated, though.  Only created
> through lots of hard work :)
> 

    There is no need to be a prophet to predict linux/abi being 99% 
symlinks right into include/{asm,linux}.

    So it is can turn out to be the same ;-)
    It just adds job for mantainers.
    (To keep symlinks in correct order ;-)))))

    But generally idea is good: keep interface separately from 
implementation.

Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.

[Jeff Garzik]

On Mon, Aug 18, 2003 at 08:54:21PM +0200, Ihar 'Philips' Filipau wrote:
> Jeff Garzik wrote:
> >>hpa IIRC suggested to create a separate directory:
> >>include/abi
> >>and then all relevant parts of the kernel should publish their public
> >>interface in the abi directory. Would that be usefull?
> >
> >
> >I support include/abi, or some other directory that segregates
> >user<->kernel shared headers away from kernel-private headers.
> >
> >I don't see how that would be auto-generated, though.  Only created
> >through lots of hard work :)
> >
> 
>    There is no need to be a prophet to predict linux/abi being 99% 
> symlinks right into include/{asm,linux}.
> 
>    So it is can turn out to be the same ;-)
>    It just adds job for mantainers.
>    (To keep symlinks in correct order ;-)))))
> 
>    But generally idea is good: keep interface separately from 
> implementation.

No, the idea is to physically separate the headers.

include/{linux,asm} is currently copied to userspace, hacked a bit,
and then shipped as the "glibc-kernheaders" package.

I would rather that the kernel developers directly maintained this
interface, by updating headers in include/abi, rather than ad-hoc by
distro people.

	Jeff

Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.

[Rob Landley]

On Monday 18 August 2003 15:04, Jeff Garzik wrote:

> >    But generally idea is good: keep interface separately from
> > implementation.
>
> No, the idea is to physically separate the headers.
>
> include/{linux,asm} is currently copied to userspace, hacked a bit,
> and then shipped as the "glibc-kernheaders" package.

Or used directly by uclibc (and linux from scratch) to build the library 
against.

> I would rather that the kernel developers directly maintained this
> interface, by updating headers in include/abi, rather than ad-hoc by
> distro people.
>
> 	Jeff

Okay, I'd like to ask about the headers thing:

I've got a project using uclibc, and build it myself, currently against the 
2.4 headers.  What's the plan for 2.6?  Everything I've seen on the subject 
is "using kernel headers directly from userspace is evil, even to build your 
libc against, but we currently offer no alternative, so go bug your libc 
maintainer and have THEM do it..."

I'm hoping I've missed something in the months I was off the list this spring, 
but haven't quite figured out what to search for in the archives yet...

Rob

Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.

[Jeff Garzik]

On Tue, Aug 19, 2003 at 08:32:24AM -0400, Rob Landley wrote:
> On Monday 18 August 2003 15:04, Jeff Garzik wrote:
> 
> > >    But generally idea is good: keep interface separately from
> > > implementation.
> >
> > No, the idea is to physically separate the headers.
> >
> > include/{linux,asm} is currently copied to userspace, hacked a bit,
> > and then shipped as the "glibc-kernheaders" package.
> 
> Or used directly by uclibc (and linux from scratch) to build the library 
> against.

Yes, this is incorrect.

Kernel developers have been telling people for years, "do not directly
include kernel headers."


> > I would rather that the kernel developers directly maintained this
> > interface, by updating headers in include/abi, rather than ad-hoc by
> > distro people.
> >
> > 	Jeff
> 
> Okay, I'd like to ask about the headers thing:
> 
> I've got a project using uclibc, and build it myself, currently against the 
> 2.4 headers.  What's the plan for 2.6?  Everything I've seen on the subject 
> is "using kernel headers directly from userspace is evil, even to build your 
> libc against, but we currently offer no alternative, so go bug your libc 
> maintainer and have THEM do it..."

Well, do you expect kernel developers to fix up every libc out there?
That's what libc maintainers exist for.  Distro guys did glibc,
(glibc-kernheaders) that covers the majority.

In any case, _this thread_ is an attempt to answer your question,
"what's the plan?"  For 2.6, I don't need include/abi happening.  Way
too late for that.  For 2.7, IMO we need it...

	Jeff

Will uclibc be supported in 2.6? (was Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.)

[Rob Landley]

On Tuesday 19 August 2003 13:26, Jeff Garzik wrote:
> On Tue, Aug 19, 2003 at 08:32:24AM -0400, Rob Landley wrote:
> > On Monday 18 August 2003 15:04, Jeff Garzik wrote:
> > > >    But generally idea is good: keep interface separately from
> > > > implementation.
> > >
> > > No, the idea is to physically separate the headers.
> > >
> > > include/{linux,asm} is currently copied to userspace, hacked a bit,
> > > and then shipped as the "glibc-kernheaders" package.
> >
> > Or used directly by uclibc (and linux from scratch) to build the library
> > against.
>
> Yes, this is incorrect.
>
> Kernel developers have been telling people for years, "do not directly
> include kernel headers."

In userspace programs, no.  But the C library has needed to include the kernel 
headers because there was nothing else defining the kernel ABI, and there 
still isn't in the actual kernel tarball.

> > I've got a project using uclibc, and build it myself, currently against
> > the 2.4 headers.  What's the plan for 2.6?  Everything I've seen on the
> > subject is "using kernel headers directly from userspace is evil, even to
> > build your libc against, but we currently offer no alternative, so go bug
> > your libc maintainer and have THEM do it..."
>
> Well, do you expect kernel developers to fix up every libc out there?

No, but I do expect the kernel to provide some way to bind to its ABI, and I'd 
expect the change you're proposing to be to be a 2.7 issue if no alternative 
has been presented yet for things that currently DO need the kernel headers.  
(Or is the official word that everybody must install this glibc package to 
use a 2.6 kernel?)

The new kernel ABI headers mentioned here don't seem to exist yet, yet what 
I'm hearing is that we're not just supposed to deprecate the old ad-hoc way 
of doing things, but completely stop using it immediately.  What exactly is 
the benefit of this supposed of to be?

Or are you saying that glibc will be the only C library supported for use with 
2.6, and uclibc users should wait until 2.7?

> That's what libc maintainers exist for.  Distro guys did glibc,
> (glibc-kernheaders) that covers the majority.

The message everybody quotes from Linus to stop having the asm symlink point 
into /usr/src/linux came out during the 2.4.0-test series.

http://groups.google.com/groups?selm=linux.kernel.8lop07%242ee%241%40penguin.transmeta.com

Now we're in 2.6.0-test and there's another change coming.  Fine.  What's the 
alternative?  If the replacement isn't ready, then this is a 2.7 thing rather 
than what people will actually be doing under 2.6.

Or are you saying linux-kernel should punt and the glibc guys are now going to 
define the linux kernel ABI for 2.6? 

> In any case, _this thread_ is an attempt to answer your question,
> "what's the plan?"  For 2.6, I don't need include/abi happening.  Way
> too late for that.  For 2.7, IMO we need it...

I'm all for doing it in 2.7.  I just want to know what I should do for 2.6.  
If there's a consensus that we're talking about 2.7 and allowing ad-hockery 
to continue in 2.6, I'll shut up. :)

> 	Jeff

Rob

Re: Will uclibc be supported in 2.6? (was Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.)

[Jeff Garzik]

Rob Landley wrote:
> I'm all for doing it in 2.7.  I just want to know what I should do for 2.6.  
> If there's a consensus that we're talking about 2.7 and allowing ad-hockery 
> to continue in 2.6, I'll shut up. :)


That's always been the consensus :)

2.6 is long past the point for major header surgery and breakage.

	Jeff

Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.

[Erik Andersen]

On Tue Aug 19, 2003 at 01:26:51PM -0400, Jeff Garzik wrote:
> > Or used directly by uclibc (and linux from scratch) to build the library 
> > against.
> 
> Yes, this is incorrect.
> 
> Kernel developers have been telling people for years, "do not directly
> include kernel headers."

<Kernel developer hat on>

Yes.  As a kernel developer I regularly tell people to make their
own private copy of the bits of kernel headers they need, to
prevent breakage when random bits in the kernel headers change.
I can't begin to count the number of applications I have fixed by
removing some kernel headers and then copying in the definition
of some random struct, adding a few ioctl defines, and then
changing everything to use types from stdint.h rather than the
kernel's internal typing.

I have also long maintained that this is incredibly stupid....
When I wrote the cdrom.h header file, for example, I wrote it to
define the interface which user space would use when talking to
the kernel.  I _designed_ that header file to be directly used by
user space, since that is the one and only spot that contains all
the relevant knowledge needed to interact with the kernel's cdrom
driver.  I mean, how else would user space know what to do?  It
is silly there needs to be N copies of the header file defining
this interface for N applications...  The fact the kernel has
mingled its internal interfaces and its external interfaces is a
serious and ugly blemish.


<uClibc maintainer hat on>

Not including kernel headers in user space is of course perfect
advice for your average piece of user space.  This is _not_
currently a reasonable request for a C library because the kernel
folk have not yet provided a reasonable alternative.  Looked at
glibc recently?  Just like uClibc, it determines the ABI of the
kernel against which it is compiled (in the case of glibc, via
the --with-headers configure option).  Distros such as RedHat and
Debian provide kernel-headers packages against which C libraries
are compiled.  Guess what those contain?  Kernel headers.  Kernel
headers which are used by user space because the kernel folk have
been too damn lazy to provide something better.

That said, for uClibc I have begun the process of eliminating the
dependence on kernel headers for random structs.  I now have arch
specific headers such as "kernel_stat.h", mainly since the kernel
headers are too inconsistant between architectures to be even
remotely usable.  But as others have noted, extracting and
sanitizing the entire kernel ABI is a huge amount of work and I
am nowhere close to done.

 -Erik

--
Erik B. Andersen             http://codepoet-consulting.com/
--This message was written using 73% post-consumer electrons--

Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.

[Jamie Lokier]

Well, I've done quite a bit of

	#ifdef __i386__
	#define __NR_futex	240
	#elif defined (__alpha__)
	#define __NR_futex	394
	#elif defined (__mips__)
	... etc. ...
	#endif

In order to distribute programs which compile with a distro's libc but
will take advantage of features in later kernels when run on them.

That's really unpleasant.  So, in revenge, here's an annoying question:

If userspace applications are ultimately compiled using Linux header
files, indirectly included via Glibc or some other libc, and the
kernel header files are GPL (version 2 only; not LGPL or any later
GPL), isn't distributing those binary applications a gross violation
of the GPL in some cases?

-- Jamie

Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.

[Jeff Garzik]

Jamie Lokier wrote:
> Well, I've done quite a bit of
> 
> 	#ifdef __i386__
> 	#define __NR_futex	240
> 	#elif defined (__alpha__)
> 	#define __NR_futex	394
> 	#elif defined (__mips__)
> 	... etc. ...
> 	#endif
> 
> In order to distribute programs which compile with a distro's libc but
> will take advantage of features in later kernels when run on them.
> 
> That's really unpleasant.  So, in revenge, here's an annoying question:

agreed.


> If userspace applications are ultimately compiled using Linux header
> files, indirectly included via Glibc or some other libc, and the
> kernel header files are GPL (version 2 only; not LGPL or any later
> GPL), isn't distributing those binary applications a gross violation
> of the GPL in some cases?

It's come up before, so it's not necessarily an original, annoying 
question ;-)

My non-lawyer guess would be, the structures and defines are required 
for Linux interoperability; that may be a factor.  static inline 
functions in headers, i.e. real code, is another matter too.

One way or another (direct inclusion, or via glibc-kernheaders pkg) the 
headers today are GPL'd not LGPL'd... so I suppose it remains the realm 
of lawyers...

IANAL,

	Jeff

Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.

[Rob Landley]

On Wednesday 20 August 2003 20:02, Jeff Garzik wrote:

> > If userspace applications are ultimately compiled using Linux header
> > files, indirectly included via Glibc or some other libc, and the
> > kernel header files are GPL (version 2 only; not LGPL or any later
> > GPL), isn't distributing those binary applications a gross violation
> > of the GPL in some cases?
...
> One way or another (direct inclusion, or via glibc-kernheaders pkg) the
> headers today are GPL'd not LGPL'd... so I suppose it remains the realm
> of lawyers...
>
> IANAL,
>
> 	Jeff

So I take it one of the goals of cleaned and pressed kernel-ABI headers for 
2.7 would be to have them distributable under LGPL?  (Just trying to be 
explicit, here...)

Rob

Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.

[Chris Friesen]

Rob Landley wrote:
> On Wednesday 20 August 2003 20:02, Jeff Garzik wrote:

>>>If userspace applications are ultimately compiled using Linux header
>>>files, indirectly included via Glibc or some other libc, and the
>>>kernel header files are GPL (version 2 only; not LGPL or any later
>>>GPL), isn't distributing those binary applications a gross violation
>>>of the GPL in some cases?

>>One way or another (direct inclusion, or via glibc-kernheaders pkg) the
>>headers today are GPL'd not LGPL'd... so I suppose it remains the realm
>>of lawyers...

> So I take it one of the goals of cleaned and pressed kernel-ABI headers for 
> 2.7 would be to have them distributable under LGPL?  (Just trying to be 
> explicit, here...)


I thought that this case (including kernel headers) was the whole point 
of the exemption in the COPYING file.  Am I missing something?

Chris

-- 
Chris Friesen                    | MailStop: 043/33/F10
Nortel Networks                  | work: (613) 765-0557
3500 Carling Avenue              | fax:  (613) 765-2986
Nepean, ON K2H 8E9 Canada        | email: cfriesen@nortelnetworks.com

Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.

[Rob Landley]

On Thursday 21 August 2003 20:50, Chris Friesen wrote:

> > So I take it one of the goals of cleaned and pressed kernel-ABI headers
> > for 2.7 would be to have them distributable under LGPL?  (Just trying to
> > be explicit, here...)
>
> I thought that this case (including kernel headers) was the whole point
> of the exemption in the COPYING file.  Am I missing something?

It's legal contortionism, and it might leave some dangling technicalities.

The Linux kernel is licensed under the GPL.  Linus's statements are just his 
interpretation of what consitutes a derived work, and hence the scope of the 
GPL.  (So it's PROBABLY not an incompatable additional license clause thingy 
that makes it "not GPL" for the purpose of linking GPL code to it.)  But lots 
of other people's code has been combined with Linus's, and they might 
consider their code under the straight GPL (sans adendum).

Whether Linus's word is final on this matter is up to a judge.  (It PROBABLY 
is, since he's the project maintainer and the project license is "GPL plus 
this memo about derived work interpretation", and anybody who contributes to 
the project without knowing that is Not Paying Attention.  Certainly all the 
contributors have had warning about this when submitting code to Linux for 
more than the past 3 years (which might be the statute of limitations, 
depending on who you ask), so for code THEY contributed we should be okay.  
The corner case is when somebody other than the code's author lifts code from 
other GPL projects and puts it in Linux, but then again that's not amazingly 
common either since how many other GPL operating system kernels do you see 
out there?  (And even then, if Linus's guide is an interpretation about the 
scope of derived works rather than a license adendum, then it may not 
actually be incompatable with the GPL, but who knows...)

All this is hair splitting, but we've all seen what happens when companies 
with more lawyers than sense decide they have no profitable business model to 
live for, buy a bunch of liquor, and pledge to take their friends out with 
them.  Nobody as ornery and stupid as SCO has sued over this fine point yet 
to give us a straw man to shoot down, so the issue hasn't been resolved in 
court yet.  I can't see SCO suing to EXTEND the reach of the GPL right now, 
so it's not an immediate pressing issue.  And if it did, Linus would be the 
main wronged party, who A) doesn't WANT damages, B) would be thrilled to 
settle out of court for a gift certificate to Wendy's or something, C) could 
obviously whip out a kernel-ABI package in an afternoon to remedy it, D) 
would probably rip out the contributions of any author who made a major stink 
about never taking even a typo correction patch from them again.

But it would be nice to clean it up beforehand anyway.  The LGPL exists for a 
reason...

(And predicting SCO's actions based on what's good for their continued 
financial or legal health would not have been a particularly accurate 
prognostication technique over the past six months...)

This whole issue is about on the level of "do not remove this mattress tag", 
by the way.  That's why people have been so complacent about it so far...

> Chris

Rob

P.S.  Even if I was a lawyer, which I'm not, you'd have to be insane to take 
legal advice from a stranger on the internet who you hadn't even paid a 
retainer to.  If you really care, go find a lawyer who understands 
intellectual property as applied to software, and the GPL specifically, and 
ask them.  (This may take some time.  I can think of four in the whole of 
north america, and two of them have asked ME for a second opinion...)

P.P.S.  Don't even ASK about the "restricted to V2, not later versions" thing.  
I'm just not going there right now...

P.P.P.S.  If you're REALLY bored, might I suggest getting a copy of "Legal 
Battles that Shaped the Computer Industry".  (It's dry reading, but where 
else are you going to find out about a lawsuit between AT&T and Franklin Ace 
that probably helped lead to both AT&T's commercialization of Unix and the 
formation of the Free Software Foundation?  Of course you have to supply half 
the context yourself...)  It's reviewed here: 
http://www.hmdc.harvard.edu/micah_altman/papers/battles.pdf

Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.

[Jeff Garzik]

Rob Landley wrote:
> On Wednesday 20 August 2003 20:02, Jeff Garzik wrote:
>>One way or another (direct inclusion, or via glibc-kernheaders pkg) the
>>headers today are GPL'd not LGPL'd... so I suppose it remains the realm
>>of lawyers...

> So I take it one of the goals of cleaned and pressed kernel-ABI headers for 
> 2.7 would be to have them distributable under LGPL?  (Just trying to be 
> explicit, here...)


Changing the status quo involves lots of pain:  querying every author if 
it's ok to change the license, and dealing with authors that don't want 
to change the license, or, rewriting the headers under a new license, etc.

I think it's best to do what we can from the technical perspective.

	Jeff

Re: [PATCH] Re: [PATCH] scsi.h uses "u8" which isn't defined.

[Sam Ravnborg]

On Mon, Aug 18, 2003 at 08:54:21PM +0200, Ihar 'Philips' Filipau wrote:
> 
>    There is no need to be a prophet to predict linux/abi being 99% 
> symlinks right into include/{asm,linux}.
Symlinks will not be included in the vanilla kernel source.
But if several files just had to be moved that would be a good start.

With potential wrappers in include/linux obviously.

	Sam