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    SubjectRe: Controversy over dynamic linking -- how to end the panic (long)
    >> 3. A kernel module loaded at runtime, after kernel build, *is not*
    >> to be considered a derivative work.
    > It doesn't much matter
    > under the GPL, anyway, so long as the in-code kernel image isn't
    > "copied or distributed".

    Broadly agree - thanks for someone pointing out the obvious
    here. Perhaps an analysis from a clause by clause reading
    would be useful.

    This seems to me to be the nub of the argument. There are three
    questions to be considered:

    1. Is development of a kernel module distributed under terms
    other than under the GPL (for instance, binary only) a
    breach of the license?

    2. If not, is distributing such a kernel module (under its
    own license) along with the kernel (otherwise correctly,
    under its license) a breach of the GPL?

    3. Is running the kernel, and loading such a kernel module,
    a breach of the kernel's license?

    In order:

    1. This hinges on whether the driver is covered by the GPL
    (definition of "Program" in 0). As the driver is clearly
    not the kernel, the test is whether it is a derived work,
    under copyright law. If we have already excluded (somehow,
    and I can't find it explicitly) inclusion of kernel headers
    from making a 'derived work', or if copyright law would
    not dictate that such inclusions made a 'derived work'
    (and I think that would be reasonably safe in a project
    of non-trivial size), then one could safely say that
    (1) would not be a breach of the license. Putting kernel
    headers under LGPL or other ammended GPL would clarify the
    matter beyond dispute.

    2. To answer (2), we assume that (1) does not apply, and that
    a kernel module is (thus) not a derived work, and that the
    GPL does not apply to it. Reading license section (2):
    "If identifiable sections of that work are not derived
    from the Program, and can be reasonably considered independent
    and separate works in themselves, then this License, and its
    terms, do not apply to those sections when you distribute
    them as separate works." and further "In addition, mere
    aggregation of another work not based on the Program
    with the Program (or with a work based on the Program) on a
    volume of a storage or distribution medium does not bring the
    other work under the scope of this License." clearly shows
    that if the distribution of the driver alone is not in
    breach of the GPL (as it is not a derived work), then,
    as a work that is not a derived work, it can be distributed
    with the kernel.

    3. The license states "Activities other than copying, distribution
    and modification are not covered by this License; they are
    outside its scope. The act of running the Program is not
    restricted, and the output from the Program is covered only
    if its contents constitute a work based on the
    Program (independent of having been made by running the Program).
    Whether that is true depends on what the Program does."
    Now it is reasonably easy to argue that loading linux kernel, and
    linking with arbitrary kernel modules after running the kernel
    is not distribution. It could easilly be argued that it is
    not copying, any more than playing a CD whose contents
    are (temporarilly) copied into buffers on the CD player is
    copying. There is a possibility that the 'work' is being
    modified. However, the work modifies itself in several ways
    (it unzips the image) as part of its normal running. Further,
    the header from Linus says "NOTE! This copyright does *not*
    cover user programs that use kernel services by normal system
    calls - this is merely considered normal use of the kernel, and
    does *not* fall under the heading of "derived work". Note the
    use of the words 'user programs' not 'user mode programs'. But
    in anycase, insmod is a user program and a user mode program,
    which uses normal system calls (documented in libraries),
    albeit to change the behaviour of the kernel. But crucially,
    let us assume this argument fails, and 'insmod' actually
    performs modification of the work. The only obligations
    on modifiers seem to be under section (2), which obligies
    modifiers to do things with modified files (none), and
    on distribution (none, of the modified work). An implication
    of this reading is that you are free to modify the linux
    kernel (or any other GPL program) in any way you want,
    and retain whatever copyright you want on such modifications,
    so long as you neither copy nor distribute the result (though
    arguably you could distribute the modifications if you did not
    distribute any part of the original). I believe that (at least
    without the parenthesised element) is entirely within both the
    letter and the spirit of the GPL - it is /not/ designed to
    keep you from developing (under copyright or otherwise)
    your own modifications, it's designed to keep you from denying
    or restricting rights of distribution of the GPL'd code if
    you distribute stuff yourself. This is set out clearly
    in the preamble.

    Areas of doubt:

    A. Are all contributed patches / files /always/ under a license
    no more restrictive than 'COPYING' - including Linus'

    B. Is it clear that inclusion of kernel headers when compiling
    a progam does not make that program a derived work of the


    A. It would be worth Linus publicising the fact (or some URL
    be added to Linux kernel postings) that patches by default
    will be assumed to be under the 'COPYING' license.

    B. It would be worth someone clearing up the status of the
    license on header files.

    C. It would be preferable if people read the COPYING file
    before commenting on license issues.

    Alex Bligh
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