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Re: Linux kernel complete licence check, Q.0 - Q.10

Scripsit Giacomo Catenazzi <cate@debian.org>

> Q.1: No copyright, no author name, no license notice!
>    [Frequent in "Makefile", header files and simple source files]
>    The licence will be the license in COPYING at the main dir?
>    thus default GNU GPL and only GPL version 2, right?

I believe we can trust that Linus & his lieutenants have made sure
that such files are indeed covered by the general license statement
for the kernel as a whole.

> Q.2: No licence notice, but a copyright notice or an author name,...
>    the same as above?


> Q.3: License but no copyright/author name, the license is still valid?


> Q.4: In the code I find the macro (i.e. in 
> linux/lib/zlib_deflate/deflate_syms.c)
>    but no more GPL references.
>    GNU GPL code? But this time according paragraph 9, valid with all
>    versions of GPL?

I'm not sure that deflate_syms.c is even copyright-protected. But if
it is, it is probably safe to interpret the MODULE_LICENSE macro as
a statement that it is licensed under GPL terms. It wouldn't hurt to
have it appear more verbosely in the file-header comment, though.

> Q.5:

>    In linux kernel can we intepret always the string "GPL" as GNU GPL?

Yes, I'd say that is a safe interpretation.

>    All GPL version are valid for license b), according GPL v.2 par. 9?

GPL#9 does state that "If the Program does not specify a version number of
this License, you may choose any version ever published by the Free Software
Foundation." However, I think that in the case of kernel sources that
is superseded by the explicit clarification at the top of the master

> Q.6:
>    : /* inflate.c -- Not copyrighted 1992 by Mark Adler
>    :   version c10p1, 10 January 1993 */

>    "Not copyrighted" == public domain?

In practise, yes. In theory, "not copyrighted" is nonsense as
"copyright" is not a verb, nor an action that someone applies to the
code. A court would try to interpret what the author *meant* by his
nonsensical statement and probably arrive at "I unconditionally waive
my copyright for this code, to the greatest extent possible by law".
This is as good as "public domain" for our purposes.

> Q.7:
>    /*
>     * linux/fs/nls_cp1250.c
>     *
>     * Charset cp1250 translation tables.
>     * Generated automatically from the Unicode and charset
>     * tables from the Unicode Organization (www.unicode.org).
>     * The Unicode to charset table has only exact mappings.
>     */

>    Generated, but:
>    a- no original sources, AFAIK
>    b- I don't know the tools (no tools, no references in kernel)

I think the questions we must ask ourselves is: If the person who
generated the sources had keep it secret that they were generated
rather than handwritten, would we perceive a problem at all? I'd say
no - the generation notice is just the author's way of saying "this is
why I feel confident that my data do not deviate from those at

If someone wanted to hack linux to do other charset translations, it
would probably be just as easy to hack the .c sources themselves than
to learn the (possibly somewhat ad hoc and undocumented) original
source for the conversion.

> Q.8:

>    linux/fs/udf/udftime.c:

>     This file is part of the GNU C Library.
>     Contributed by Paul Eggert (eggert@twinsun.com).
>     The GNU C Library is free software; you can redistribute it and/or
>     modify it under the terms of the GNU Library General Public License as

>    linux kernel is not "GNU C Library". There are license problems because
>    the text is "GNU C Library is ..."

I don't see a problem here. The relevant information is that everyone
who has a copyright on the file's content have agreed to it being
licensed under the GPL. That includes agreeing to it going into Linux.

> Q.9:

>   * Copyright (C) 1995-1997  Paul H. Hargrove
>   * This file may be distributed under the terms of the GNU General 
>     Public License.
>   * The code in this file is derived from code which is copyright
>   * 1986, 1989, 1990 by Abacus Research and Development, Inc. (ARDI)
>   * It is used here by the permission of ARDI's president Cliff Matthews.

>    All the derived code is is GPL? It seems that original code was not GPL.

Yes, but it seems that the copyright holder for the original code has
explicitly allowed the derivate to be licensed under GPL, which is

Henning Makholm                                    "*Vi vil ha wienerbrød!*"

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