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2024-02-14Add SPDX license identifier into 0BSD source code files.Lasse Collin1-0/+2
2024-02-14Change most public domain parts to 0BSD.Lasse Collin1-3/+0
Translations and doc/xz-file-format.txt and doc/lzma-file-format.txt were not touched. COPYING.0BSD was added.
2023-07-31Docs: Fix typos found by codespellDimitri Papadopoulos Orfanos1-1/+1
2022-09-08liblzma: Vaccinate against an ill patch from RHEL/CentOS 7.Lasse Collin1-0/+18
RHEL/CentOS 7 shipped with 5.1.2alpha, including the threaded encoder that is behind #ifdef LZMA_UNSTABLE in the API headers. In 5.1.2alpha these symbols are under XZ_5.1.2alpha in liblzma.map. API/ABI compatibility tracking isn't done between development releases so newer releases didn't have XZ_5.1.2alpha anymore. Later RHEL/CentOS 7 updated xz to 5.2.2 but they wanted to keep the exported symbols compatible with 5.1.2alpha. After checking the ABI changes it turned out that >= 5.2.0 ABI is backward compatible with the threaded encoder functions from 5.1.2alpha (but not vice versa as fixes and extensions to these functions were made between 5.1.2alpha and 5.2.0). In RHEL/CentOS 7, XZ Utils 5.2.2 was patched with xz-5.2.2-compat-libs.patch to modify liblzma.map: - XZ_5.1.2alpha was added with lzma_stream_encoder_mt and lzma_stream_encoder_mt_memusage. This matched XZ Utils 5.1.2alpha. - XZ_5.2 was replaced with XZ_5.2.2. It is clear that this was an error; the intention was to keep using XZ_5.2 (XZ_5.2.2 has never been used in XZ Utils). So XZ_5.2.2 lists all symbols that were listed under XZ_5.2 before the patch. lzma_stream_encoder_mt and _mt_memusage are included too so they are listed both here and under XZ_5.1.2alpha. The patch didn't add any __asm__(".symver ...") lines to the .c files. Thus the resulting liblzma.so exports the threaded encoder functions under XZ_5.1.2alpha only. Listing the two functions also under XZ_5.2.2 in liblzma.map has no effect without matching .symver lines. The lack of XZ_5.2 in RHEL/CentOS 7 means that binaries linked against unpatched XZ Utils 5.2.x won't run on RHEL/CentOS 7. This is unfortunate but this alone isn't too bad as the problem is contained within RHEL/CentOS 7 and doesn't affect users of other distributions. It could also be fixed internally in RHEL/CentOS 7. The second problem is more serious: In XZ Utils 5.2.2 the API headers don't have #ifdef LZMA_UNSTABLE for obvious reasons. This is true in RHEL/CentOS 7 version too. Thus now programs using new APIs can be compiled without an extra #define. However, the programs end up depending on symbol version XZ_5.1.2alpha (and possibly also XZ_5.2.2) instead of XZ_5.2 as they would with an unpatched XZ Utils 5.2.2. This means that such binaries won't run on other distributions shipping XZ Utils >= 5.2.0 as they don't provide XZ_5.1.2alpha or XZ_5.2.2; they only provide XZ_5.2 (and XZ_5.0). (This includes RHEL/CentOS 8 as the patch luckily isn't included there anymore with XZ Utils 5.2.4.) Binaries built by RHEL/CentOS 7 users get distributed and then people wonder why they don't run on some other distribution. Seems that people have found out about the patch and been copying it to some build scripts, seemingly curing the symptoms but actually spreading the illness further and outside RHEL/CentOS 7. The ill patch seems to be from late 2016 (RHEL 7.3) and in 2017 it had spread at least to EasyBuild. I heard about the events only recently. :-( This commit splits liblzma.map into two versions: one for GNU/Linux and another for other OSes that can use symbol versioning (FreeBSD, Solaris, maybe others). The Linux-specific file and the matching additions to .c files add full compatibility with binaries that have been built against a RHEL/CentOS-patched liblzma. Builds for OSes other than GNU/Linux won't get the vaccine as they should be immune to the problem (I really hope that no build script uses the RHEL/CentOS 7 patch outside GNU/Linux). The RHEL/CentOS compatibility symbols XZ_5.1.2alpha and XZ_5.2.2 are intentionally put *after* XZ_5.2 in liblzma_linux.map. This way if one forgets to #define HAVE_SYMBOL_VERSIONS_LINUX when building, the resulting liblzma.so.5 will have lzma_stream_encoder_mt@@XZ_5.2 since XZ_5.2 {...} is the first one that lists that function. Without HAVE_SYMBOL_VERSIONS_LINUX @XZ_5.1.2alpha and @XZ_5.2.2 will be missing but that's still a minor problem compared to only having lzma_stream_encoder_mt@@XZ_5.1.2alpha! The "local: *;" line was moved to XZ_5.0 so that it doesn't need to be moved around. It doesn't matter where it is put. Having two similar liblzma_*.map files is a bit silly as it is, at least for now, easily possible to generate the generic one from the Linux-specific file. But that adds extra steps and increases the risk of mistakes when supporting more than one build system. So I rather maintain two files in parallel and let validate_map.sh check that they are in sync when "make mydist" is run. This adds .symver lines for lzma_stream_encoder_mt@XZ_5.2.2 and lzma_stream_encoder_mt_memusage@XZ_5.2.2 even though these weren't exported by RHEL/CentOS 7 (only @@XZ_5.1.2alpha was for these two). I added these anyway because someone might misunderstand the RHEL/CentOS 7 patch and think that @XZ_5.2.2 (@@XZ_5.2.2) versions were exported too. At glance one could suggest using __typeof__ to copy the function prototypes when making aliases. However, this doesn't work trivially because __typeof__ won't copy attributes (lzma_nothrow, lzma_pure) and it won't change symbol visibility from hidden to default (done by LZMA_API()). Attributes could be copied with __copy__ attribute but that needs GCC 9 and a fallback method would be needed anyway. This uses __symver__ attribute with GCC >= 10 and __asm__(".symver ...") with everything else. The attribute method is required for LTO (-flto) support with GCC. Using -flto with GCC older than 10 is now broken on GNU/Linux and will not be fixed (can silently result in a broken liblzma build that has dangerously incorrect symbol versions). LTO builds with Clang seem to work with the traditional __asm__(".symver ...") method. Thanks to Boud Roukema for reporting the problem and discussing the details and testing the fix.
2014-08-05liblzma: Add support for lzma_block.ignore_check.Lasse Collin1-1/+1
Note that this slightly changes how lzma_block_header_decode() has been documented. Earlier it said that the .version is set to the lowest required value, but now it says that the .version field is kept unchanged if possible. In practice this doesn't affect any old code, because before this commit the only possible .version was 0.
2013-03-23liblzma: Add lzma_block_uncomp_encode().Lasse Collin1-31/+63
This also adds a new internal function lzma_block_buffer_bound64() which is similar to lzma_block_buffer_bound() but uses uint64_t instead of size_t.
2012-07-17liblzma: Make the use of lzma_allocator const-correct.Lasse Collin1-2/+2
There is a tiny risk of causing breakage: If an application assigns lzma_stream.allocator to a non-const pointer, such code won't compile anymore. I don't know why anyone would do such a thing though, so in practice this shouldn't cause trouble. Thanks to Jan Kratochvil for the patch.
2011-04-11liblzma: Validate encoder arguments better.Lasse Collin1-6/+12
The biggest problem was that the integrity check type wasn't validated, and e.g. lzma_easy_buffer_encode() would create a corrupt .xz Stream if given an unsupported Check ID. Luckily applications don't usually try to use an unsupport Check ID, so this bug is unlikely to cause many real-world problems.
2010-05-26Rename MIN() and MAX() to my_min() and my_max().Lasse Collin1-1/+1
This should avoid some minor portability issues.
2009-05-26Make the raw value of the Check field available to applicationsLasse Collin1-0/+1
via lzma_block structure. This changes ABI but not doesn't break API.
2009-04-13Put the interesting parts of XZ Utils into the public domain.Lasse Collin1-10/+3
Some minor documentation cleanups were made at the same time.
2009-02-02Modify LZMA_API macro so that it works on Windows withLasse Collin1-2/+2
other compilers than MinGW. This may hurt readability of the API headers slightly, but I don't know any better way to do this.
2009-01-20Add some single-call buffer-to-buffer coding functions.Lasse Collin1-0/+305