aboutsummaryrefslogtreecommitdiff
path: root/src/liblzma/liblzma.map (unfollow)
AgeCommit message (Collapse)AuthorFilesLines
2022-09-08liblzma: Vaccinate against an ill patch from RHEL/CentOS 7.Lasse Collin1-116/+0
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.
2022-08-22Bump version number for 5.3.3alpha.larhzu/v5.3.3alphaLasse Collin1-1/+1
2022-03-07liblzma: Add threaded .xz decompressor.Lasse Collin1-0/+1
I realize that this is about a decade late. Big thanks to Sebastian Andrzej Siewior for the original patch. I made a bunch of smaller changes but after a while quite a few things got rewritten. So any bugs in the commit were created by me.
2021-10-28Bump the version number for 5.3.2alpha.larhzu/v5.3.2alphaLasse Collin1-1/+1
2021-09-17liblzma: Fix liblzma.map for the lzma_microlzma_* symbols.Lasse Collin1-2/+2
This should have been part of d267d109c370a40b502e73f8664b154b15e4f253. Thanks to Gao Xiang.
2021-01-14liblzma: Add EROFS LZMA encoder and decoder.Lasse Collin1-0/+2
Right now this is just a planned extra-compact format for use in the EROFS file system in Linux. At this point it's possible that the format will either change or be abandoned and removed completely. The special thing about the encoder is that it uses the output-size-limited encoding added in the previous commit. EROFS uses fixed-sized blocks (e.g. 4 KiB) to hold compressed data so the compressors must be able to create valid streams that fill the given block size.
2018-04-29Bump the version number to 5.3.1alpha.larhzu/v5.3.1alphaLasse Collin1-1/+1
2017-04-24liblzma: Add lzma_file_info_decoder().Lasse Collin1-1/+6
2014-12-21Bump version and soname for 5.2.0.Lasse Collin1-1/+1
I know that soname != app version, but I skip AGE=1 in -version-info to make the soname match the liblzma version anyway. It doesn't hurt anything as long as it doesn't conflict with library versioning rules.
2014-09-14Bump the version number to 5.1.4beta.larhzu/v5.1.4betaLasse Collin1-1/+1
2014-06-18liblzma: Add lzma_cputhreads().Lasse Collin1-0/+1
2013-10-26Bump the version number to 5.1.3alpha.larhzu/v5.1.3alphaLasse Collin1-1/+1
2013-03-23liblzma: Add lzma_block_uncomp_encode().Lasse Collin1-0/+1
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.
2012-12-14Make the progress indicator smooth in threaded mode.Lasse Collin1-0/+1
This adds lzma_get_progress() to liblzma and takes advantage of it in xz. lzma_get_progress() collects progress information from the thread-specific structures so that fairly accurate progress information is available to applications. Adding a new function seemed to be a better way than making the information directly available in lzma_stream (like total_in and total_out are) because collecting the information requires locking mutexes. It's waste of time to do it more often than the up to date information is actually needed by an application.
2012-07-04Bump the version number to 5.1.2alpha.larhzu/v5.1.2alphaLasse Collin1-1/+1
2011-05-28liblzma: Use symbol versioning.Lasse Collin1-0/+105
Symbol versioning is enabled by default on GNU/Linux, other GNU-based systems, and FreeBSD. I'm not sure how stable this is, so it may need backward-incompatible changes before the next release. The idea is that alpha and beta symbols are considered unstable and require recompiling the applications that use those symbols. Once a symbol is stable, it may get extended with new features in ways that don't break compatibility with older ABI & API. The mydist target runs validate_map.sh which should catch some probable problems in liblzma.map. Otherwise I would forget to update the map file for new releases.