This is a private function that locks the lock much like the regular
pthread_mutex_lock(), but causes the corresponding unlock operation to
always assume there may be other waiters. This is useful in case some
waiters are made to wait on the mutex's futex directly, without going
through pthread_mutex_lock(). This is going to be used by the condition
variable implementation in the next commit.
pthread_mutex is now an actual "sleeping" mutex, and not just a
spinlock! It still has a fast path that only uses atomics and (in the
successful case) returns immediately without sleeping. In case of
contention, it calls futex_wait(), which lets the kernel scheduler put
this thread to sleep, *and* lets it know exactly when to consider
scheduling it again.
These are convinient wrappers over the most used futex operations.
futex_wait() also does some smarts for timeout and clock handling.
Use the new futex_wait() instead of a similar private helper in
LibPthread.
Depending on the driver, the second buffer may not be located right
after the first, e.g. it may be page aligned. This removes this
assumption and queries the driver for the appropriate offset.
Some devices may require DMA transfers to flush the updated buffer
areas prior to flipping. For those devices we track the areas that
require flushing prior to the next flip. For devices that do not
support flipping, but require flushing, we'll simply flush after
updating the front buffer.
This also adds a small optimization that skips these steps entirely for
a screen that doesn't have any updates that need to be rendered.
These were preventing some AK classes from using the AK Concepts header
due to the non-strictly namespaced ConversionSpecifier::Unsigned, and
are not used as their underlying value, so enum classes are more
appropriate anyways.
When creating uninitialized storage for variables, we need to make sure
that the alignment is correct. Fixes a KUBSAN failure when running
kernels compiled with Clang.
In `Syscalls/socket.cpp`, we can simply use local variables, as
`sockaddr_un` is a POD type.
Along with moving the `alignas` specifier to the correct member,
`AK::Optional`'s internal buffer has been made non-zeroed by default.
GCC emitted bogus uninitialized memory access warnings, so we now use
`__builtin_launder` to tell the compiler that we know what we are doing.
This might disable some optimizations, but judging by how GCC failed to
notice that the memory's initialization is dependent on `m_has_value`,
I'm not sure that's a bad thing.
We regularily need to flush many rectangles, so instead of making many
expensive ioctl() calls to the framebuffer driver, collect the
rectangles and only make one call. And if we have too many rectangles
then it may be cheaper to just update the entire region, in which case
we simply convert them all into a union and just flush that one
rectangle instead.
A POSIX-compatibility fix was introduced in 64740a0214 to make the
compilation of the `diffutils` port work, which expected a
`char* const* argv` signature.
And indeed, the POSIX spec does not mention permutation of `argv`:
https://pubs.opengroup.org/onlinepubs/9699919799/functions/getopt.html
However, most implementations do modify `argv` as evidenced by
documentation such as:
https://refspecs.linuxbase.org/LSB_5.0.0/LSB-Core-generic
/LSB-Core-generic/libutil-getopt-3.html
"The function prototype was aligned with POSIX 1003.1-2008 (ISO/IEC
9945-2009) despite the fact that it modifies argv, and the library
maintainers are unwilling to change this."
Change the behavior back to permutate `argc` to allow for the following
command line argument order to work again:
unzip ./file.zip -o target-dir
Without this change, `./file.zip` in the example above would have been
ignored completely.
Other software might not expect these to be defined and behave
differently if they _are_ defined, e.g. scummvm which checks if
the TODO macro is defined and fails to build if it is.
This implements the dladdr() function which lets the caller look up
the symbol name, symbol address as well as library name and library
base address for an arbitrary address.
This ensures the store to mutex->lock doesn't get re-ordered before
the store to mutex->owner which could otherwise result in a locked
owner-less mutex if another thread tries to acquire the lock at
the same time.
POSIX (`errno(3p)`) states that errno should not be set to zero.
This helps with applications that don't expect errno to get updated
unless an intermediate syscall also fails.
Previously there was no way to output an empty value into the shadow
file entries when the spwd members were disabled. This would cause new
user entries to the shadow file to be cluttered with disabled values.
This commit checks if the spwd member value is diabled (-1) and will
output as appropriate.
wint_t is also not supposed to be defined by sys/types.h, but should
be defined in wchar.h instead. Since we require it for our definition of
btowc, let's move it to the correct place.
