No description
76e0622b68
Currently we scan the /include/ directive as two tokens, the
"/include/" keyword itself, then the string giving the file name to
include. We use a special scanner state to keep the two linked
together, and use the scanner state stack to keep track of the
original state while we're parsing the two /include/ tokens.
This does mean that we need to enable the 'stack' option in flex,
which results in a not-easily-suppressed warning from the flex
boilerplate code. This is mildly irritating.
However, this two-token scanning of the /include/ directive also has
some extremely strange edge cases, because there are a variety of
tokens recognized in all scanner states, including INCLUDE. For
example the following strange dts file:
/include/ /dts-v1/;
/ {
/* ... */
};
Will be processed successfully with the /include/ being effectively
ignored: the '/dts-v1/' and ';' are recognized even in INCLUDE state,
then the ';' transitions us to PROPNODENAME state, throwing away
INCLUDE, and the previous state is never popped off the stack. Or
for another example this construct:
foo /include/ = "somefile.dts"
will be parsed as though it were:
foo = /include/ "somefile.dts"
Again, the '=' is scanned without leaving INCLUDE state, then the next
string triggers the include logic.
And finally, we use a different regexp for the string with the
included filename than the normal string regexpt, which is also
potentially weird.
This patch, therefore, cleans up the lexical handling of the /include/
directive. Instead of the INCLUDE state, we instead scan the whole
include directive, both keyword and filename as a single token. This
does mean a bit more complexity in extracting the filename out of
yytext, but I think it's worth it to avoid the strageness described
above. It also means it's no longer possible to put a comment between
the /include/ and the filename, but I'm really not very worried about
breaking files using such a strange construct.
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|---|---|---|
| Documentation | ||
| libfdt | ||
| scripts | ||
| tests | ||
| .gitignore | ||
| checks.c | ||
| convert-dtsv0-lexer.l | ||
| data.c | ||
| dtc-lexer.l | ||
| dtc-parser.y | ||
| dtc.c | ||
| dtc.h | ||
| flattree.c | ||
| fstree.c | ||
| ftdump.c | ||
| GPL | ||
| livetree.c | ||
| Makefile | ||
| Makefile.dtc | ||
| README.license | ||
| srcpos.c | ||
| srcpos.h | ||
| TODO | ||
| treesource.c | ||
Licensing and contribution policy of dtc and libfdt =================================================== This dtc package contains two pieces of software: dtc itself, and libfdt which comprises the files in the libfdt/ subdirectory. These two pieces of software, although closely related, are quite distinct. dtc does not incoporate or rely on libfdt for its operation, nor vice versa. It is important that these two pieces of software have different license conditions. As the copyright banners in each source file attest, dtc is licensed under the GNU GPL. The full text of the GPL can be found in the file entitled 'GPL' which should be included in this package. dtc code, therefore, may not be incorporated into works which do not have a GPL compatible license. libfdt, however, is GPL/BSD dual-licensed. That is, it may be used either under the terms of the GPL, or under the terms of the 2-clause BSD license (aka the ISC license). The full terms of that license are given in the copyright banners of each of the libfdt source files. This is, in practice, equivalent to being BSD licensed, since the terms of the BSD license are strictly more permissive than the GPL. I made the decision to license libfdt in this way because I want to encourage widespread and correct usage of flattened device trees, including by proprietary or otherwise GPL-incompatible firmware or tools. Allowing libfdt to be used under the terms of the BSD license makes that it easier for vendors or authors of such software to do so. This does mean that libfdt code could be "stolen" - say, included in a proprietary fimware and extended without contributing those extensions back to the libfdt mainline. While I hope that doesn't happen, I believe the goal of allowing libfdt to be widely used is more important than avoiding that. libfdt is quite small, and hardly rocket science; so the incentive for such impolite behaviour is small, and the inconvenience caused therby is not dire. Licenses such as the LGPL which would allow code to be used in non-GPL software, but also require contributions to be returned were considered. However, libfdt is designed to be used in firmwares and other environments with unusual technical constraints. It's difficult to anticipate all possible changes which might be needed to meld libfdt into such environments and so difficult to suitably word a license that puts the boundary between what is and isn't permitted in the intended place. Again, I judged encouraging widespread use of libfdt by keeping the license terms simple and familiar to be the more important goal. **IMPORTANT** It's intended that all of libfdt as released remain permissively licensed this way. Therefore only contributions which are released under these terms can be merged into the libfdt mainline. David Gibson <david@gibson.dropbear.id.au> (principal original author of dtc and libfdt) 2 November 2007