Old versions of Clang reported the unsupported function attribute and
__crc32d() function as warnings instead of errors, so the feature test
passed when it shouldn't have, causing a compile error at build time.
-Werror was added to this feature test to fix this. The change is not
needed for CMake because check_c_source_compiles() also performs
linking and the error is caught then.
Thanks to Sebastian Andrzej Siewior for reporting this.
If xz is given a directory, it should look like this:
$ xz /usr/bin
xz: /usr/bin: Is a directory, skipping
The Landlock rules didn't allow opening directories for reading:
$ xz /usr/bin
xz: /usr/bin: Permission denied
The simplest fix was to allow opening directories for reading.
While it's a bit silly to allow it solely for the error message,
it shouldn't make the sandbox significantly weaker.
The single-file use case (like when called from GNU tar) is
still as strict as possible: all Landlock restrictions are
enabled before (de)compression starts.
Support for the old MinGW was dropped. Only MinGW-w64 with GCC
is supported now.
The script now supports also cross-compilation from GNU/Linux
(tests are not run). MSYS2 and also the old MSYS 1.0.11 work
for building on Windows. The i686 and x86_64 toolchains must
be in PATH to build both 32-bit and 64-bit versions.
Parallel builds are done if "nproc" from GNU coreutils is available.
MinGW-w64 runtime copyright information file was renamed from
COPYING-Windows.txt to COPYING.MinGW-w64-runtime.txt which
is the filename used by MinGW-w64 itself. Its existence
is now mandatory, it's checked at the beginning of the script.
The file TODO is no longer copied to the package.
The original code was good enough for supporting GNU/Linux
and a few others but it wasn't very portable.
CMake doesn't support Solaris Studio's -xldscope=hidden.
If it ever does, things should still work with this commit
as Solaris Studio supports not only its own __global but also
the GNU C __attribute__((visibility("default"))). Support for the
attribute was added in 2007 to Sun Studio 12 compiler version 5.9.
-O3 doesn't seem useful for speed but it makes the code bigger.
CMake makes is difficult for users to simply override the
optimization level: CFLAGS / CMAKE_C_FLAGS aren't helpful because
they go before CMAKE_C_FLAGS_RELEASE. Of course, users can override
CMAKE_C_FLAGS_RELEASE directly but then they have to remember to
add also -DNDEBUG to disable assertions.
This commit changes -O3 to -O2 in CMAKE_C_FLAGS_RELEASE if and only if
CMAKE_C_FLAGS_RELEASE cache variable doesn't already exist. So if
a custom value is passed on the command line (or reconfiguring an
already-configured build), the cache variable won't be modified.
In contrast to Automake, skipping of this test when decoders
are disabled is handled at CMake side instead of test_scripts.sh
because CMake-build doesn't create config.h.
Compared to the Autotools-based build, this has simpler handling
for the shell (@POSIX_SHELL@) and extra PATH entry for the scripts
(configure has --enable-path-for-scripts=PREFIX). The simpler
metho should be enough for non-ancient systems and Solaris.
It helps that cmake_install.cmake doesn't parallelize installation
so symlinks can be created so that the target is always known to
exist (a requirement on Windows in some cases).
This bumps the minimum CMake version from 3.13 to 3.14 to use
file(CREATE_LINK ...). It could be made to work on 3.13 by
calling "cmake -E create_symlink" but it's uglier code and
slower in "make install". 3.14 should be a reasonable version
to require nowadays, especially since the Autotools build
is still the primary build system for most OSes.
If gettext tools are available, the .po files listed in po/LINGUAS
are converted using msgfmt. This allows building with translations
directly from xz.git without Autotools.
If gettext tools aren't available, the Autotools-created .gmo files
in the "po" directory will be used. This allows CMake-based build
to use translations from Autotools-generated tarball.
If translation support is found (Intl_FOUND) but both the
gettext tools and the pre-generated .gmo files are missing,
then "make" will fail.
This makes these sandboxing methods stricter when no files are
created or deleted. That is, it's a middle ground between the
initial sandbox and the strictest single-file-to-stdout sandbox:
this allows opening files for reading but output has to go to stdout.
Linux 6.7 added support for ABI version 4 which restricts
TCP connections which xz won't need and thus those can be
forbidden now. Since the ABI version is handled at runtime,
supporting version 4 won't cause any compatibility issues.
Note that new enough kernel headers are required to get
version 4 support enabled at build time.
Landlock is now always used just like pledge(2) is: first in more
permissive mode and later (under certain common conditions) in
a strict mode that doesn't allow opening more files.
I put pledge(2) first in sandbox.c because it's the simplest API
to use and still somewhat fine-grained for basic applications.
So it's the simplest thing to understand for anyone reading sandbox.c.
Also explicitly initialize progress_automatic to make it clear
that it can be read before message_init() sets it. Static variable
was initialized to false by default already so this is only for
clarity.
GCC docs promise that it works and a few other compilers do
too. Clang/LLVM is documented source code only but unsurprisingly
it behaves the same as others on x86-64 at least. But the
certainly-portable way is good enough here so use that.
Jia Tan