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2022-11-24liblzma: Add lzma_filters_update() support to the multi-threaded encoder.Lasse Collin1-8/+88
A tiny downside of this is that now a 1-4 tiny allocations are made for every Block because each worker thread needs its own copy of the filter chain.
2022-11-24liblzma: Refactor to use lzma_filters_free().Lasse Collin1-9/+2
lzma_filters_free() sets the options to NULL and ids to LZMA_VLI_UNKNOWN so there is no need to do it by caller; the filter arrays will always be left in a safe state. Also use memcpy() instead of a loop to copy a filter chain when it is known to be safe to copy LZMA_FILTERS_MAX + 1 (even if the elements past the terminator might be uninitialized).
2022-11-24liblzma: Fix another invalid free() after memory allocation failure.Lasse Collin1-0/+4
This time it can happen when lzma_stream_encoder_mt() is used to reinitialize an existing multi-threaded Stream encoder and one of 1-4 tiny allocations in lzma_filters_copy() fail. It's very similar to the previous bug 10430fbf3820dafd4eafd38ec8be161a6978ed2b, happening with an array of lzma_filter structures whose old options are freed but the replacement never arrives due to a memory allocation failure in lzma_filters_copy().
2022-09-08liblzma: Vaccinate against an ill patch from RHEL/CentOS 7.Lasse Collin1-0/+42
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.
2022-02-22liblzma: Check the return value of lzma_index_append() in threaded encoder.Lasse Collin1-2/+5
If lzma_index_append() failed (most likely memory allocation failure) it could have gone unnoticed and the resulting .xz file would have an incorrect Index. Decompressing such a file would produce the correct uncompressed data but then an error would occur when verifying the Index field.
2021-01-24liblzma: Fix a wrong comment in stream_encoder_mt.c.Lasse Collin1-3/+7
2021-01-09liblzma: Make lzma_outq usable for threaded decompression too.Lasse Collin1-19/+33
Before this commit all output queue buffers were allocated as a single big allocation. Now each buffer is allocated separately when needed. Used buffers are cached to avoid reallocation overhead but the cache will keep only one buffer size at a time. This should make things work OK in the decompression where most of the time the buffer sizes will be the same but with some less common files the buffer sizes may vary. While this should work fine, it's still a bit preliminary and may even get reverted if it turns out to be useless for decompression.
2019-06-24liblzma: Add a comment.Lasse Collin1-1/+1
2019-05-11spellingAntoine Cœur1-1/+1
2016-11-21liblzma: Avoid multiple definitions of lzma_coder structures.Lasse Collin1-56/+68
Only one definition was visible in a translation unit. It avoided a few casts and temp variables but seems that this hack doesn't work with link-time optimizations in compilers as it's not C99/C11 compliant. Fixes: http://www.mail-archive.com/xz-devel@tukaani.org/msg00279.html
2014-11-25liblzma: Verify the filter chain in threaded encoder initialization.Lasse Collin1-3/+6
This way an invalid filter chain is detected at the Stream encoder initialization instead of delaying it to the first call to lzma_code() which triggers the initialization of the actual filter encoder(s).
2014-11-10liblzma: Fix lzma_mt.preset in lzma_stream_encoder_mt_memusage().Lasse Collin1-2/+1
It read the filter chain from a wrong variable. This is a similar bug that was fixed in 9494fb6d0ff41c585326f00aa8f7fe58f8106a5e.
2014-01-29liblzma: Fix lzma_mt.preset not working with lzma_stream_encoder_mt().Lasse Collin1-2/+2
It read the filter chain from a wrong variable.
2013-10-02liblzma: Support LZMA_FULL_FLUSH and _BARRIER in threaded encoder.Lasse Collin1-16/+39
Now --block-list=SIZES works with in the threaded mode too, although the performance is still bad due to the use of LZMA_FULL_FLUSH instead of the new LZMA_FULL_BARRIER.
2013-09-17Add native threading support on Windows.Lasse Collin1-47/+36
Now liblzma only uses "mythread" functions and types which are defined in mythread.h matching the desired threading method. Before Windows Vista, there is no direct equivalent to pthread condition variables. Since this package doesn't use pthread_cond_broadcast(), pre-Vista threading can still be kept quite simple. The pre-Vista code doesn't use anything that wasn't already available in Windows 95, so the binaries should run even on Windows 95 if someone happens to care.
2013-06-23liblzma: Avoid a warning about a shadowed variable.Lasse Collin1-2/+2
On Mac OS X wait() is declared in <sys/wait.h> that we include one way or other so don't use "wait" as a variable name. Thanks to Christian Kujau.
2013-03-23liblzma: Use lzma_block_buffer_bound64() in threaded encoder.Lasse Collin1-16/+50
Now it uses lzma_block_uncomp_encode() if the data doesn't fit into the space calculated by lzma_block_buffer_bound64().
2013-03-23liblzma: Fix another deadlock in the threaded encoder.Lasse Collin1-3/+6
This race condition could cause a deadlock if lzma_end() was called before finishing the encoding. This can happen with xz with debugging enabled (non-debugging version doesn't call lzma_end() before exiting).
2012-12-14Make the progress indicator smooth in threaded mode.Lasse Collin1-5/+72
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.
2012-07-17liblzma: Make the use of lzma_allocator const-correct.Lasse Collin1-8/+8
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.
2011-10-23liblzma: Fix a deadlock in the threaded encoder.Lasse Collin1-1/+3
It was triggered when reinitializing the encoder, e.g. when encoding two files.
2011-04-11liblzma: Add lzma_stream_encoder_mt() for threaded compression.Lasse Collin1-0/+1011
This is the simplest method to do threading, which splits the uncompressed data into blocks and compresses them independently from each other. There's room for improvement especially to reduce the memory usage, but nevertheless, this is a good start.