Commit Graph

76 Commits

Author SHA1 Message Date
Jia Tan b34b6a9912 liblzma: Initialize lzma_lz_encoder pointers with NULL.
This fixes the recent change to lzma_lz_encoder that used memzero
instead of the NULL constant. On some compilers the NULL constant
(always 0) may not equal the NULL pointer (this only needs to guarentee
to not point to valid memory address).

Later code compares the pointers to the NULL pointer so we must
initialize them with the NULL pointer instead of 0 to guarentee
code correctness.
2023-12-20 21:38:39 +08:00
Jia Tan 183a62f0b5 liblzma: Set all values in lzma_lz_encoder to NULL after allocation.
The first member of lzma_lz_encoder doesn't necessarily need to be set
to NULL since it will always be set before anything tries to use it.
However the function pointer members must be set to NULL since other
functions rely on this NULL value to determine if this behavior is
supported or not.

This fixes a somewhat serious bug, where the options_update() and
set_out_limit() function pointers are not set to NULL. This seems to
have been forgotten since these function pointers were added many years
after the original two (code() and end()).

The problem is that by not setting this to NULL we are relying on the
memory allocation to zero things out if lzma_filters_update() is called
on a LZMA1 encoder. The function pointer for set_out_limit() is less
serious because there is not an API function that could call this in an
incorrect way. set_out_limit() is only called by the MicroLZMA encoder,
which must use LZMA1 where set_out_limit() is always set. Its currently
not possible to call set_out_limit() on an LZMA2 encoder at this time.

So calling lzma_filters_update() on an LZMA1 encoder had undefined
behavior since its possible that memory could be manipulated so the
options_update member pointed to a different instruction sequence.

This is unlikely to be a bug in an existing application since it relies
on calling lzma_filters_update() on an LZMA1 encoder in the first place.
For instance, it does not affect xz because lzma_filters_update() can
only be used when encoding to the .xz format.

This is fixed by using memzero() to set all members of lzma_lz_encoder
to NULL after it is allocated. This ensures this mistake will not occur
here in the future if any additional function pointers are added.
2023-12-16 20:51:38 +08:00
Jia Tan 1a1bb381db liblzma: Tweak a comment. 2023-12-16 20:30:55 +08:00
Jia Tan 2ade7246e7 liblzma: Add missing comments to lz_encoder.h. 2023-11-09 01:21:53 +08:00
Lasse Collin 41113fe30a liblzma: Use lzma_attr_visibility_hidden on private extern declarations.
These variables are internal to liblzma and not exposed in the API.
2023-10-30 18:06:25 +02:00
Jia Tan f6667702bf liblzma: Change quoting style from `...' to '...'.
This was done for both internal and API headers.
2023-09-24 22:09:47 +08:00
Dimitri Papadopoulos Orfanos 42df7c7aa1
Docs: Fix typos found by codespell 2023-07-31 20:02:21 +08:00
Jia Tan d0f33d672a liblzma: Creates IS_ENC_DICT_SIZE_VALID() macro.
This creates an internal liblzma macro to test if the dictionary size
is valid for encoding.
2023-05-11 22:28:45 +08:00
Lasse Collin 31c21c734b liblzma: Silence another warning from -Wsign-conversion in a 32-bit build.
It doesn't warn on a 64-bit system because truncating
a ptrdiff_t (signed long) to uint32_t is diagnosed under
-Wconversion by GCC and -Wshorten-64-to-32 by Clang.
2023-01-12 05:38:48 +02:00
Lasse Collin 6c886cc5b3 Fix warnings from clang -Wdocumentation. 2023-01-12 03:11:40 +02:00
Lasse Collin 5f22bd2d37 liblzma: Remove lzma_lz_decoder_uncompressed() as it's now unused. 2022-11-28 10:51:03 +02:00
Lasse Collin 218394958c liblzma: Pass the Filter ID to LZ encoder and decoder.
This allows using two Filter IDs with the same
initialization function and data structures.
2022-11-27 18:20:33 +02:00
Lasse Collin 3be88ae071 liblzma: Allow nice_len 2 and 3 even if match finder requires 3 or 4.
That is, if the specified nice_len is smaller than the minimum
of the match finder, silently use the match finder's minimum value
instead of reporting an error. The old behavior is annoying to users
and it complicates xz options handling too.
2022-11-24 23:23:55 +02:00
Lasse Collin eb0f1450ad liblzma: Use __attribute__((__constructor__)) if available.
This uses it for CRC table initializations when using --disable-small.
It avoids mythread_once() overhead. It also means that then
--disable-small --disable-threads is thread-safe if this attribute
is supported.
2022-11-14 16:00:52 +02:00
Jia Tan 61f8ec804a liblzma: Refactor lzma_mf_is_supported() to use a switch-statement. 2022-07-25 18:30:10 +03:00
Lasse Collin 9595a3119b liblzma: Add optional autodetection of LZMA end marker.
Turns out that this is needed for .lzma files as the spec in
LZMA SDK says that end marker may be present even if the size
is stored in the header. Such files are rare but exist in the
real world. The code in liblzma is so old that the spec didn't
exist in LZMA SDK back then and I had understood that such
files weren't possible (the lzma tool in LZMA SDK didn't
create such files).

This modifies the internal API so that LZMA decoder can be told
if EOPM is allowed even when the uncompressed size is known.
It's allowed with .lzma and not with other uses.

Thanks to Karl Beldan for reporting the problem.
2022-07-13 22:24:07 +03:00
Lasse Collin 625f4c7c99 liblzma: Add rough support for output-size-limited encoding in LZMA1.
With this it is possible to encode LZMA1 data without EOPM so that
the encoder will encode as much input as it can without exceeding
the specified output size limit. The resulting LZMA1 stream will
be a normal LZMA1 stream without EOPM. The actual uncompressed size
will be available to the caller via the uncomp_size pointer.

One missing thing is that the LZMA layer doesn't inform the LZ layer
when the encoding is finished and thus the LZ may read more input
when it won't be used. However, this doesn't matter if encoding is
done with a single call (which is the planned use case for now).
For proper multi-call encoding this should be improved.

This commit only adds the functionality for internal use.
Nothing uses it yet.
2021-01-14 18:58:13 +02:00
Lasse Collin 7136f1735c Rename unaligned_read32ne to read32ne, and similarly for the others. 2019-12-31 00:47:49 +02:00
Lasse Collin 8ce679125d liblzma: Fix a buggy comment. 2019-06-25 23:15:21 +03:00
Lasse Collin 608517b9b7 liblzma: Remove incorrect uses of lzma_attribute((__unused__)).
Caught by clang -Wused-but-marked-unused.
2019-06-24 22:50:36 +03:00
Lasse Collin c460f6defe liblzma: Fix one more unaligned read to use unaligned_read16ne(). 2019-06-02 00:50:59 +03:00
Lasse Collin 2a22de439e liblzma: Avoid memcpy(NULL, foo, 0) because it is undefined behavior.
I should have always known this but I didn't. Here is an example
as a reminder to myself:

    int mycopy(void *dest, void *src, size_t n)
    {
        memcpy(dest, src, n);
        return dest == NULL;
    }

In the example, a compiler may assume that dest != NULL because
passing NULL to memcpy() would be undefined behavior. Testing
with GCC 8.2.1, mycopy(NULL, NULL, 0) returns 1 with -O0 and -O1.
With -O2 the return value is 0 because the compiler infers that
dest cannot be NULL because it was already used with memcpy()
and thus the test for NULL gets optimized out.

In liblzma, if a null-pointer was passed to memcpy(), there were
no checks for NULL *after* the memcpy() call, so I cautiously
suspect that it shouldn't have caused bad behavior in practice,
but it's hard to be sure, and the problematic cases had to be
fixed anyway.

Thanks to Jeffrey Walton.
2019-05-13 20:05:17 +03:00
Antoine Cœur 2fb0ddaa55 spelling 2019-05-11 20:52:37 +03:00
Lasse Collin d4a0462abe liblzma: Avoid multiple definitions of lzma_coder structures.
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
2016-11-21 20:24:50 +02:00
Lasse Collin 14115f84a3 liblzma: Make Valgrind happier with optimized (gcc -O2) liblzma.
When optimizing, GCC can reorder code so that an uninitialized
value gets used in a comparison, which makes Valgrind unhappy.
It doesn't happen when compiled with -O0, which I tend to use
when running Valgrind.

Thanks to Rich Prohaska. I remember this being mentioned long
ago by someone else but nothing was done back then.
2015-11-04 23:14:00 +02:00
Lasse Collin f243f5f44c liblzma: Silence more uint32_t vs. size_t warnings. 2015-03-07 22:01:00 +02:00
Lasse Collin fec88d41e6 liblzma: Silence harmless Valgrind errors.
Thanks to Torsten Rupp for reporting this. I had
forgotten to run Valgrind before the 5.2.0 release.
2015-01-26 20:39:28 +02:00
Lasse Collin 71e1437ab5 liblzma: Use lzma_memcmplen() in the BT3 match finder.
I had missed this when writing the commit
5db75054e9.

Thanks to Jun I Jin.
2014-08-04 19:25:58 +03:00
Lasse Collin 5db75054e9 liblzma: Use lzma_memcmplen() in the match finders.
This doesn't change the match finder output.
2014-07-25 21:15:07 +03:00
Lasse Collin da1718f266 liblzma: Use lzma_alloc_zero() in LZ encoder initialization.
This avoids a memzero() call for a newly-allocated memory,
which can be expensive when encoding small streams with
an over-sized dictionary.

To avoid using lzma_alloc_zero() for memory that doesn't
need to be zeroed, lzma_mf.son is now allocated separately,
which requires handling it separately in normalize() too.

Thanks to Vincenzo Innocente for reporting the problem.
2014-05-25 21:45:56 +03:00
Lasse Collin 3778db1be5 liblzma: Make the use of lzma_allocator const-correct.
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.
2012-07-17 18:19:59 +03:00
Lasse Collin 324cde7a86 liblzma: Remove unneeded semicolon. 2011-06-16 12:15:29 +03:00
Lasse Collin 4c6e146df9 Add underscores to attributes (__attribute((__foo__))). 2011-05-17 11:54:38 +03:00
Lasse Collin 77fe5954cd liblzma: Adjust default depth calculation for HC3 and HC4.
It was 8 + nice_len / 4, now it is 4 + nice_len / 4.
This allows faster settings at lower nice_len values,
even though it seems that I won't use automatic depth
calcuation with HC3 and HC4 in the presets.
2010-09-03 12:28:41 +03:00
Lasse Collin b5fbab6123 Silence a bogus Valgrind warning.
When using -O2 with GCC, it liked to swap two comparisons
in one "if" statement. It's otherwise fine except that
the latter part, which is seemingly never executed, got
executed (nothing wrong with that) and then triggered
warning in Valgrind about conditional jump depending on
uninitialized variable. A few people find this annoying
so do things a bit differently to avoid the warning.
2010-06-02 23:09:22 +03:00
Lasse Collin 920a69a8d8 Rename MIN() and MAX() to my_min() and my_max().
This should avoid some minor portability issues.
2010-05-26 10:36:46 +03:00
Lasse Collin eb7d51a3fa Collection of language fixes to comments and docs.
Thanks to Jonathan Nieder.
2010-02-12 13:16:15 +02:00
Lasse Collin e330fb7e6b Fix wrong indentation caused by incorrect settings
in the text editor.
2009-11-15 12:54:45 +02:00
Lasse Collin 418d64a32e Fix a design error in liblzma API.
Originally the idea was that using LZMA_FULL_FLUSH
with Stream encoder would read the filter chain
from the same array that was used to intialize the
Stream encoder. Since most apps wouldn't use
LZMA_FULL_FLUSH, most apps wouldn't need to keep
the filter chain available after initializing the
Stream encoder. However, due to my mistake, it
actually required keeping the array always available.

Since setting the new filter chain via the array
used at initialization time is not a nice way to do
it for a couple of reasons, this commit ditches it
and introduces lzma_filters_update(). This new function
replaces also the "persistent" flag used by LZMA2
(and to-be-designed Subblock filter), which was also
an ugly thing to do.

Thanks to Alexey Tourbin for reminding me about the problem
that Stream encoder used to require keeping the filter
chain allocated.
2009-11-14 18:59:19 +02:00
Lasse Collin ebfb2c5e1f Use a tuklib module for integer handling.
This replaces bswap.h and integer.h.

The tuklib module uses <byteswap.h> on GNU,
<sys/endian.h> on *BSDs and <sys/byteorder.h>
on Solaris, which may contain optimized code
like inline assembly.
2009-10-04 22:57:12 +03:00
Lasse Collin 3782b3fee4 Use unaligned access (if possible) on both endiannesses
in lz_encoder_hash.h.
2009-10-02 11:28:17 +03:00
Lasse Collin c5f68b5cc7 Make liblzma produce the same output on both endiannesses.
Seems that it is a problem in some cases if the same
version of XZ Utils produces different output on different
endiannesses, so this commit fixes that problem. The output
will still vary between different XZ Utils versions, but I
cannot avoid that for now.

This commit bloatens the code on big endian systems by 1 KiB,
which should be OK since liblzma is bloated already. ;-)
2009-10-02 11:03:26 +03:00
Lasse Collin 4ab7b16b95 A few grammar fixes.
Thanks to Christian Weisgerber for pointing out some of these.
2009-09-12 14:07:36 +03:00
Lasse Collin 18a4233a53 Fix a couple of warnings. 2009-09-11 09:25:09 +03:00
Lasse Collin 3ce1916c83 Fix data corruption in LZ/LZMA2 encoder.
Thanks to Jonathan Stott for the bug report.
2009-08-16 22:15:13 +03:00
Lasse Collin f42ee98166 Build system fixes
Don't use libtool convenience libraries to avoid recently
discovered long-standing subtle but somewhat severe bugs
in libtool (at least 1.5.22 and 2.2.6 are affected). It
was found when porting XZ Utils to Windows
<http://lists.gnu.org/archive/html/libtool/2009-06/msg00070.html>
but the problem is significant also e.g. on GNU/Linux.

Unless --disable-shared is passed to configure, static
library built from a set of convenience libraries will
contain PIC objects. That is, while libtool builds non-PIC
objects too, only PIC objects will be used from the
convenience libraries. On 32-bit x86 (tested on mobile XP2400+),
using PIC instead of non-PIC makes the decompressor 10 % slower
with the default CFLAGS.

So while xz was linked against static liblzma by default,
it got the slower PIC objects unless --disable-shared was
used. I tend develop and benchmark with --disable-shared
due to faster build time, so I hadn't noticed the problem
in benchmarks earlier.

This commit also adds support for building Windows resources
into liblzma and executables.
2009-06-30 17:09:57 +03:00
Lasse Collin 1c9360b7d1 Fix @variables@ to $(variables) in Makefile.am files.
Fix the ordering of libgnu.a and LTLIBINTL on the linker
command line and added missing LTLIBINTL to tests/Makefile.am.
2009-06-26 14:47:31 +03:00
Lasse Collin 02ddf09bc3 Put the interesting parts of XZ Utils into the public domain.
Some minor documentation cleanups were made at the same time.
2009-04-13 11:27:40 +03:00
Lasse Collin e79c42d854 Fix off-by-one in LZ decoder.
Fortunately, this bug had no security risk other than accepting
some corrupt files as valid.
2009-04-10 11:17:02 +03:00
Lasse Collin 0e27028d74 Add a separate internal function to initialize the CRC32
table, which is used also by LZ encoder. This was needed
because calling lzma_crc32() and ignoring the result is
a no-op due to lzma_attr_pure.
2009-02-08 18:24:50 +02:00