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Author SHA1 Message Date
Jia Tan
c5f6d79cc9 Build: Add support for ARM64 CRC32 instruction detection.
This adds --enable-arm64-crc32/--disable-arm64-crc32 (enabled by
default) for using the ARM64 CRC32 instruction. This can be disabled if
one knows the binary will never need to run on an ARM64 machine
with this instruction extension.
2024-02-01 20:09:09 +08:00
Jia Tan
440a2eccb0 liblzma: Add RISC-V BCJ filter.
The new Filter ID is 0x0B.

Thanks to Chien Wong <m@xv97.com> for the initial version of the Filter,
the xz CLI updates, and the Autotools build system modifications.

Thanks to Igor Pavlov for his many contributions to the design of
the filter.
2024-01-23 23:05:41 +08:00
Jia Tan
c26812c5b2 Build: Update website URL. 2024-01-19 23:08:14 +08:00
Lasse Collin
419f55f9df liblzma: Avoid extern lzma_crc32_clmul() and lzma_crc64_clmul().
A CLMUL-only build will have the crcxx_clmul() inlined into
lzma_crcxx(). Previously a jump to the extern lzma_crcxx_clmul()
was needed. Notes about shared liblzma on ELF platforms:

  - On platforms that support ifunc and -fvisibility=hidden, this
    was silly because CLMUL-only build would have that single extra
    jump instruction of extra overhead.

  - On platforms that support neither -fvisibility=hidden nor linker
    version script (liblzma*.map), jumping to lzma_crcxx_clmul()
    would go via PLT so a few more instructions of overhead (still
    not a big issue but silly nevertheless).

There was a downside with static liblzma too: if an application only
needs lzma_crc64(), static linking would make the linker include the
CLMUL code for both CRC32 and CRC64 from crc_x86_clmul.o even though
the CRC32 code wouldn't be needed, thus increasing code size of the
executable (assuming that -ffunction-sections isn't used).

Also, now compilers are likely to inline crc_simd_body()
even if they don't support the always_inline attribute
(or MSVC's __forceinline). Quite possibly all compilers
that build the code do support such an attribute. But now
it likely isn't a problem even if the attribute wasn't supported.

Now all x86-specific stuff is in crc_x86_clmul.h. If other archs
The other archs can then have their own headers with their own
is_clmul_supported() and crcxx_clmul().

Another bonus is that the build system doesn't need to care if
crc_clmul.c is needed.

is_clmul_supported() stays as inline function as it's not needed
when doing a CLMUL-only build (avoids a warning about unused function).
2024-01-11 14:29:42 +02:00
Jia Tan
5feb09266f Build: Allow sandbox to be configured for just xzdec.
If xz is disabled, then xzdec can still use the sandbox.
2023-12-20 22:43:44 +08:00
Jia Tan
ffb456593d Build: Change --enable-ifunc handling.
Some compilers support __attribute__((__ifunc__())) even though the
dynamic linker does not. The compiler is able to create the binary
but it will fail on startup. So it is not enough to just test if
the attribute is supported.

The default value for enable_ifunc is now auto, which will attempt
to compile a program using __attribute__((__ifunc__())). There are
additional checks in this program if glibc is being used or if it
is running on FreeBSD.

Setting --enable-ifunc will skip this test and always enable
__attribute__((__ifunc__())), even if is not supported.
2023-11-30 20:04:42 +08:00
Jia Tan
148e20607e Build: Fix text wrapping in an output message. 2023-10-31 21:54:11 +08:00
Lasse Collin
88588b1246 Build: Detect -fsanitize= in CFLAGS and incompatible build options.
Now configure will fail if -fsanitize= is found in CFLAGS
and sanitizer-incompatible ifunc or Landlock sandboxing
would be used. These are incompatible with one or more sanitizers.
It's simpler to reject all -fsanitize= uses instead of trying to
pass those that might not cause problems.

CMake-based build was updated similarly. It lets the configuration
finish (SEND_ERROR instead of FATAL_ERROR) so that both error
messages can be seen at once.
2023-10-25 20:18:04 +03:00
Lasse Collin
8276c7f41c xz: Support basic sandboxing with Linux Landlock (ABI versions 1-3).
It is enabled only when decompressing one file to stdout,
similar to how Capsicum is used.

Landlock was added in Linux 5.13.
2023-10-22 19:03:52 +03:00
Lasse Collin
2e2cd11535 Simplify detection of Capsicum support.
This removes support for FreeBSD 10.0 and 10.1 which used
<sys/capability.h> instead of <sys/capsicum.h>. Support for
FreeBSD 10.1 ended on 2016-12-31. So now FreeBSD >= 10.2 is
required to enable Capsicum support.

This also removes support for Capsicum on Linux (libcaprights)
which seems to have been unmaintained since 2017 and Linux 4.11:
https://github.com/google/capsicum-linux
2023-10-22 19:03:52 +03:00
Lasse Collin
1c1a8c3ee4 Build: Check for clock_gettime() even if not using POSIX threads.
See the new comment in the code.

This also makes the check for clock_gettime() run with MinGW-w64
with which we don't want to use clock_gettime(). The previous
commit already took care of this situation.
2023-10-22 18:59:45 +03:00
Jia Tan
8c0f9376f5 liblzma: Create crc_clmul.c.
Both crc32_clmul() and crc64_clmul() are now exported from
crc32_clmul.c as lzma_crc32_clmul() and lzma_crc64_clmul(). This
ensures that is_clmul_supported() (now lzma_is_clmul_supported()) is
not duplicated between crc32_fast.c and crc64_fast.c.

Also, it encapsulates the complexity of the CLMUL implementations into a
single file and reduces the complexity of crc32_fast.c and crc64_fast.c.
Before, CLMUL code was present in crc32_fast.c, crc64_fast.c, and
crc_common.h.

During the conversion, various cleanups were applied to code (thanks to
Lasse Collin) including:

- Require using semicolons with MASK_/L/H/LH macros.
- Variable typing and const handling improvements.
- Improvements to comments.
- Fixes to the pragmas used.
- Removed unneeded variables.
- Whitespace improvements.
- Fixed CRC_USE_GENERIC_FOR_SMALL_INPUTS handling.
- Silenced warnings and removed the need for some #pragmas
2023-10-18 23:54:36 +08:00
Lasse Collin
092d21db2e Build: Update the comment about -Werror usage in checks. 2023-09-26 17:24:15 +03:00
Lasse Collin
a37a276338 Build: Fix __attribute__((ifunc(...))) detection with clang -Wall.
Now if user-supplied CFLAGS contains -Wall -Wextra -Wpedantic
the two checks that need -Werror will still work.

At CMake side there is add_compile_options(-Wall -Wextra)
but it didn't affect the -Werror tests. So with both Autotools
and CMake only user-supplied CFLAGS could make the checks fail
when they shouldn't.

This is not a full fix as things like -Wunused-macros in
user-supplied CFLAGS will still cause problems with both
GCC and Clang.
2023-09-26 15:00:43 +03:00
Lasse Collin
9c42f93693 Build: Fix underquoted AC_LANG_SOURCE.
It made no practical difference in this case.
2023-09-26 13:51:31 +03:00
Lasse Collin
9f1444a8a5 Build: Silence two Autoconf warnings.
There were two uses of AC_COMPILE_IFELSE that didn't use
AC_LANG_SOURCE and Autoconf warned about these. The omission
had been intentional but it turned out that this didn't do
what I thought it would.

Autoconf 2.71 manual gives an impression that AC_LANG_SOURCE
inserts all #defines that have been made with AC_DEFINE so
far (confdefs.h). The idea was that omitting AC_LANG_SOURCE
would mean that only the exact code included in the
AC_COMPILE_IFELSE call would be compiled.

With C programs this is not true: the #defines get added without
AC_LANG_SOURCE too. There seems to be no neat way to avoid this.
Thus, with the C language at least, adding AC_LANG_SOURCE makes
no other difference than silencing a warning from Autoconf. The
generated "configure" remains identical. (Docs of AC_LANG_CONFTEST
say that the #defines have been inserted since Autoconf 2.63b and
that AC_COMPILE_IFELSE uses AC_LANG_CONFTEST. So the behavior is
documented if one also reads the docs of macros that one isn't
calling directly.)

Any extra code, including #defines, can cause problems for
these two tests because these tests must use -Werror.
CC=clang CFLAGS=-Weverything is the most extreme example.
It enables -Wreserved-macro-identifier which warns about
#define __EXTENSIONS__ 1 because it begins with two underscores.
It's possible to write a test file that passes -Weverything but
it becomes impossible when Autoconf inserts confdefs.h.

So this commit adds AC_LANG_SOURCE to silence Autoconf warnings.
A different solution is needed for -Werror tests.
2023-09-26 13:50:19 +03:00
Jia Tan
be012b8097 Build: Change quoting style from `...' to '...'. 2023-09-24 22:09:16 +08:00
Lasse Collin
74b0e900c9 Build: Omit -Wc99-c11-compat since it warns about _Noreturn. 2023-09-22 20:06:26 +03:00
Jia Tan
de574404c4 Build: Conditionally allow win95 threads and --enable-small.
When the compiler supports __attribute__((__constructor__))
mythread_once() is never used, even with --enable-small. A configuration
with win95 threads and --enable-small will compile and be thread safe so
it can be allowed.

This isn't a very common configuration since MSVC does not support
__attribute__((__constructor__)), but MINGW32 and CLANG32 environments
for MSYS2 can use win95 threads and have
__attribute__((__constructor__)) support.
2023-08-09 20:35:16 +08:00
Dimitri Papadopoulos Orfanos
42df7c7aa1
Docs: Fix typos found by codespell 2023-07-31 20:02:21 +08:00
Lasse Collin
b4cf7a2822 Minor tweaks to style and comments. 2023-06-27 23:56:06 +08:00
Hans Jansen
23b5c36fb7 Add ifunc check to configure.ac
configure.ac will now verify if __attribute__((__ifunc__())) can be used in
the build system. If so, HAVE_FUNC_ATTRIBUTE_IFUNC will be defined to 1.
2023-06-27 15:33:15 +03:00
Lasse Collin
8be136f667 Build: Add a comment that AC_PROG_CC_C99 is needed for Autoconf 2.69.
It's obsolete in Autoconf >= 2.70 and just an alias for AC_PROG_CC
but Autoconf 2.69 requires AC_PROG_CC_C99 to get a C99 compiler.
2023-03-21 14:07:51 +02:00
Lasse Collin
53cc475f26 Build: configure.ac: Use AS_IF and AS_CASE where required.
This makes no functional difference in the generated configure
(at least with the Autotools versions I have installed) but this
change might prevent future bugs like the one that was just
fixed in the commit 5a5bd7f871.
2023-03-21 14:04:37 +02:00
Lasse Collin
5a5bd7f871 Build: Fix --disable-threads breaking the building of shared libs.
This is broken in the releases 5.2.6 to 5.4.2. A workaround
for these releases is to pass EGREP='grep -E' as an argument
to configure in addition to --disable-threads.

The problem appeared when m4/ax_pthread.m4 was updated in
the commit 6629ed929c which
introduced the use of AC_EGREP_CPP. AC_EGREP_CPP calls
AC_REQUIRE([AC_PROG_EGREP]) to set the shell variable EGREP
but this was only executed if POSIX threads were enabled.
Libtool code also has AC_REQUIRE([AC_PROG_EGREP]) but Autoconf
omits it as AC_PROG_EGREP has already been required earlier.
Thus, if not using POSIX threads, the shell variable EGREP
would be undefined in the Libtool code in configure.

ax_pthread.m4 is fine. The bug was in configure.ac which called
AX_PTHREAD conditionally in an incorrect way. Using AS_CASE
ensures that all AC_REQUIREs get always run.

Thanks to Frank Busse for reporting the bug.
Fixes: https://github.com/tukaani-project/xz/issues/45
2023-03-21 13:11:49 +02:00
Lasse Collin
b473a92891 Change a few HTTP URLs to HTTPS.
The xz man page timestamp was intentionally left unchanged.
2023-03-18 15:56:07 +02:00
Lasse Collin
c97d12f300 Doxygen: Refactor Doxyfile.in to doxygen/Doxyfile.
Instead of having Doxyfile.in configured by Autoconf, the Doxyfile
can have the tags that need to be configured piped into the doxygen
command through stdin with the overrides after Doxyfile's contents.

Going forward, the documentation should be generated in two different
modes: liblzma or internal.

liblzma is useful for most users. It is the documentation for just
the liblzma API header files. This is the default.

internal is for people who want to understand how xz and liblzma work.
It might be useful for people who want to contribute to the project.
2023-03-17 01:42:28 +08:00
Lasse Collin
2ee86d20e4 Build: Use only the generic symbol versioning on MicroBlaze.
On MicroBlaze, GCC 12 is broken in sense that
__has_attribute(__symver__) returns true but it still doesn't
support the __symver__ attribute even though the platform is ELF
and symbol versioning is supported if using the traditional
__asm__(".symver ...") method. Avoiding the traditional method is
good because it breaks LTO (-flto) builds with GCC.

See also: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101766

For now the only extra symbols in liblzma_linux.map are the
compatibility symbols with the patch that spread from RHEL/CentOS 7.
These require the use of __symver__ attribute or __asm__(".symver ...")
in the C code. Compatibility with the patch from CentOS 7 doesn't
seem valuable on MicroBlaze so use liblzma_generic.map on MicroBlaze
instead. It doesn't require anything special in the C code and thus
no LTO issues either.

An alternative would be to detect support for __symver__
attribute in configure.ac and CMakeLists.txt and fall back
to __asm__(".symver ...") but then LTO would be silently broken
on MicroBlaze. It sounds likely that MicroBlaze is a special
case so let's treat it as a such because that is simpler. If
a similar issue exists on some other platform too then hopefully
someone will report it and this can be reconsidered.

(This doesn't do the same fix in CMakeLists.txt. Perhaps it should
but perhaps CMake build of liblzma doesn't matter much on MicroBlaze.
The problem breaks the build so it's easy to notice and can be fixed
later.)

Thanks to Vincent Fazio for reporting the problem and proposing
a patch (in the end that solution wasn't used):
https://github.com/tukaani-project/xz/pull/32
2023-02-17 20:48:28 +02:00
Lasse Collin
a15a7552f9 Build: Avoid different quoting style in --enable-doxygen doc. 2023-01-26 17:51:06 +02:00
Jia Tan
bbf71b69eb Doxygen: Make Doxygen only produce liblzma API documentation by default.
Doxygen is now configurable in autotools only with
--enable-doxygen=[api|all]. The default is "api", which will only
generate HTML output for liblzma API functions. The LaTex documentation
output was also disabled.
2023-01-20 00:51:12 +08:00
Lasse Collin
a8bb8358d1 Build: Omit -Wmissing-noreturn from the default warnings.
It's not that important. It can be annoying in builds that
disable many features since in those cases the tests programs
will correctly trigger this warning with Clang.
2023-01-12 13:04:05 +02:00
Lasse Collin
5ce6ddc221 Build: Make configure add more warning flags for GCC and Clang.
-Wstrict-aliasing was removed from the list since it is enabled
by -Wall already.

A normal build is clean with these on GNU/Linux x86-64 with
GCC 12.2.0 and Clang 14.0.6.
2023-01-12 04:17:24 +02:00
Lasse Collin
ceb8050117 Build: Require that _mm_set_epi64x() is usable to enable CLMUL support.
VS2013 doesn't have _mm_set_epi64x() so this way CLMUL gets
disabled with VS2013.

Thanks to Iouri Kharon for the bug report.
2023-01-08 00:20:42 +02:00
Lasse Collin
73c9e6d6b9 Build: Fix config.h comments. 2023-01-02 17:05:07 +02:00
Jia Tan
74dae7d300 Build: No longer require HAVE_DECL_CLOCK_MONOTONIC to always be set.
Previously, if threading was enabled HAVE_DECL_CLOCK_MONOTONIC would always
be set to 0 or 1. However, this macro was needed in xz so if xz was not
built with threading and HAVE_DECL_CLOCK_MONOTONIC was not defined but
HAVE_CLOCK_GETTIME was, it caused a warning during build. Now,
HAVE_DECL_CLOCK_MONOTONIC has been renamed to HAVE_CLOCK_MONOTONIC and
will only be set if it is 1.
2022-12-30 23:34:31 +08:00
Lasse Collin
764955e2d4 Change the bug report address.
It forwards to me and Jia Tan.

Also update the IRC reference in README as #tukaani was moved
to Libera Chat long ago.
2022-11-30 18:08:34 +02:00
Lasse Collin
06824396b2 Build: Don't put GNU/Linux-specific symbol versions into static liblzma.
It not only makes no sense to put symbol versions into a static library
but it can also cause breakage.

By default Libtool #defines PIC if building a shared library and
doesn't define it for static libraries. This is documented in the
Libtool manual. It can be overriden using --with-pic or --without-pic.
configure.ac detects if --with-pic or --without-pic is used and then
gives an error if neither --disable-shared nor --disable-static was
used at the same time. Thus, in normal situations it works to build
both shared and static library at the same time on GNU/Linux,
only --with-pic or --without-pic requires that only one type of
library is built.

Thanks to John Paul Adrian Glaubitz from Debian for reporting
the problem that occurred on ia64:
https://www.mail-archive.com/xz-devel@tukaani.org/msg00610.html
2022-11-24 14:52:44 +02:00
Lasse Collin
f644473a21 liblzma: Add fast CRC64 for 32/64-bit x86 using SSSE3 + SSE4.1 + CLMUL.
It also works on E2K as it supports these intrinsics.

On x86-64 runtime detection is used so the code keeps working on
older processors too. A CLMUL-only build can be done by using
-msse4.1 -mpclmul in CFLAGS and this will reduce the library
size since the generic implementation and its 8 KiB lookup table
will be omitted.

On 32-bit x86 this isn't used by default for now because by default
on 32-bit x86 the separate assembly file crc64_x86.S is used.
If --disable-assembler is used then this new CLMUL code is used
the same way as on 64-bit x86. However, a CLMUL-only build
(-msse4.1 -mpclmul) won't omit the 8 KiB lookup table on
32-bit x86 due to a currently-missing check for disabled
assembler usage.

The configure.ac check should be such that the code won't be
built if something in the toolchain doesn't support it but
--disable-clmul-crc option can be used to unconditionally
disable this feature.

CLMUL speeds up decompression of files that have compressed very
well (assuming CRC64 is used as a check type). It is know that
the CLMUL code is significantly slower than the generic code for
tiny inputs (especially 1-8 bytes but up to 16 bytes). If that
is a real-world problem then there is already a commented-out
variant that uses the generic version for small inputs.

Thanks to Ilya Kurdyukov for the original patch which was
derived from a white paper from Intel [1] (published in 2009)
and public domain code from [2] (released in 2016).

[1] https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/fast-crc-computation-generic-polynomials-pclmulqdq-paper.pdf
[2] https://github.com/rawrunprotected/crc
2022-11-14 23:05:46 +02:00
Lasse Collin
ac10b1b362 Build: Omit x86_64 from --enable-assembler.
It didn't do anything. There are only 32-bit x86 assembly files
and it feels likely that new files won't be added as intrinsics
in C are more portable across toolchains and OSes.
2022-11-14 17:58:07 +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
Lasse Collin
0538db038f liblzma: Add .lz (lzip) decompression support (format versions 0 and 1).
Support for format version 0 was removed from lzip 1.18 for some
reason. .lz format version 0 files are rare (and old) but some
source packages were released in this format, and some people might
have personal files in this format too. It's very little extra code
to support it along side format version 1 so this commits adds
support for both.

The Sync Flush marker extentension to the original .lz format
version 1 isn't supported. It would require changes to the
LZMA decoder itself. Such files are very rare anyway.

See the API doc for lzma_lzip_decoder() for more details about
the .lz format support.

Thanks to Michał Górny for the original patch.
2022-11-09 14:24:20 +02:00
Lasse Collin
cf118c0146 Build: Clarify comment in configure.ac about SSE2. 2022-10-31 16:26:05 +02:00
Lasse Collin
aad3c609ff Build: Remove obsolete commented-out lines from configure.ac. 2022-10-31 16:16:37 +02:00
Lasse Collin
a4b214b93a Build: Use AC_CONFIG_HEADERS instead of the ancient AC_CONFIG_HEADER.
We require Autoconf >= 2.69 and that has AC_CONFIG_HEADERS.

There is a warning about AC_PROG_CC_C99 being obsolete but
it cannot be removed because it is needed with Autoconf 2.69.
2022-10-25 23:45:03 +03:00
Lasse Collin
59c4d6e139 Build: Add configure option --disable-microlzma.
MicroLZMA was made for EROFS and used by erofs-utils.
It might be used by something else in the future but
those wanting a smaller build for specific situations
can now disable this rarely-needed feature.
2022-10-25 23:28:34 +03:00
Lasse Collin
563288ea70 xz: Add support for OpenBSD's pledge() sandbox. 2022-10-25 21:30:48 +03:00
Lasse Collin
ecb966de30 liblzma: Add experimental ARM64 BCJ filter with a temporary Filter ID.
That is, the Filter ID will be changed once the design is final.
The current version will be removed. So files created with the
tempoary Filter ID won't be supported in the future.
2022-09-19 20:23:46 +03:00
Lasse Collin
913ddc5572 liblzma: Vaccinate against an ill patch from RHEL/CentOS 7.
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.
2022-09-08 15:01:29 +03:00
Jia Tan
4d80b463a1 Build: Don't allow empty LIST in --enable-match-finders=LIST.
It's enforced only when a match finder is needed, that is,
when LZMA1 or LZMA2 encoder is enabled.
2022-07-25 18:20:01 +03:00
Lasse Collin
4773608554 Build: Enable Automake's parallel test harness.
It has been the default for quite some time already and
the old serial harness isn't discouraged. The downside is
that with parallel tests one cannot print progress info or
other diagnostics to the terminal; all output from the tests
will be in the log files only. But now that the compression
tests are separated the parallel tests will speed things up.
2022-05-23 21:31:36 +03:00