user_mutex: Refactor locking and unblocking mechanism.

Suppose the following scenario:

1. Thread A holds a mutex.

2. Thread B goes to acquire the mutex, winds up in kernel waiting.

3. Thread A unlocks; first unsets the LOCKED flag.
As WAITING is set, it calls the kernel; but instead of processing
this immediately, the thread is suspended for any reason (locks,
reschedule, etc.)

4. Thread B hits a timeout, or a signal. It then unblocks in the kernel,
which causes the WAITING flag to be unset.

5. Thread C goes to acquire the lock. It sets the LOCKED flag.
It sees the WAITING flag is not set, so it returns at once,
having successfully acquired the lock.

6. Thread A, suspended back in step 3, resumes.

Now we encounter the problem. Under the previous code, the following
would occur.

7. Thread A sees that no threads are waiting. It thus unsets the LOCKED
flag, and returns from the kernel. Now we have a mutex theoretically
held by thread C but which (illegally) has no LOCKED flag set!

8. Some other thread tries to acquire the lock, and succeeds, for LOCKED
is not set. We now have one lock owned by two separate threads.
That's very bad!

The solution, in this commit, is to (1) switch from using "atomic_or"
to lock mutexes, to using "atomic_test_and_set", and (2) mandate that
_kern_unblock_mutex must be invoked with the mutex already unlocked.

Trying to solve the problem with (2) but without (1) produces other
complications and would overall be more complicated. For instance,
all existing userland code expected that it would set LOCKED, but then
check LOCKED|WAITING. If _kern_mutex_unlock does not unset LOCKED,
then whichever thread sets LOCKED when it was previously unset is
now the mutex's undisputed owner, and if it fails to notice this,
would deadlock.

That could have been solved with extra checks at all lock points, but
then that would mean locks would not be acquired "fairly": it would
be possible for any thread to race with an unlocking thread, and
acquire the lock before the kernel had a chance to wake anyone up.

Given how fast atomics can be, and how slow invoking the kernel is
comparatively, that would probably make our mutexes extremely "unfair."
This would not violate the POSIX specification, but it does seem like
a dangerous choice to make in implementing these APIs.

Linux's "futex" API, which our API bears some similarities to, requires
at least one atomic test-and-set for an uncontended acquisition,
and multiple atomics more for even the simplest case of contended
acquisition. If it works for them, it should work for us, too.

Fixes #18436.

Change-Id: Ib8c28acf04ce03234fe738e41aa0969ca1917540
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6537
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

pthread: add pthread_{getname_np,setname_npp}

- These two functions imported for Linux/BSD compability.

Signed-off-by: Han Pengfei <pengphei@qq.com>
Change-Id: I3e9cada26f1ed043bfaed83e8185dcfff3bd71e2
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5746
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>

libs/posix: Implemented new locale functions

Implemented the missing POSIX functions in <locale.h>:
newlocale, duplocale, uselocale, and freelocale, and also
provided missing type definitions for <locale.h>.

Implemented missing POSIX locale-based function variants.

Modified LocaleBackend so that it could support thread-local
locales.

Some glibc-like locale-related variables supporting
ctype and printf family of functions have also been updated
to reflect the thread-local variables present in the latest
glibc sources.

As there have been some modifications to global symbols
in libroot, libroot_stubs.c has been regenerated.

Bug: #17168
Change-Id: Ibf296c58c47d42d1d1dfb2ce64042442f2679431
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5351
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

wait_for_thread_etc: expose as syscall/make public.

* This will be needed for the following commit that implements
`pthread_tryjoin_np` and `pthread_timedjoin_np`.

Change-Id: Idccb1aa588d6d10825294d14925d9bd046b65f19
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5098
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

libroot: remove delete_driver_settings

It is not present in BeOS R5 and it just call unload_driver_settings.

Replace delete_driver_settings usages with unload_driver_settings.
Keep the symbol on x86 for binary compatibility.

Change-Id: I1382710e3a4cb5c65d1249ea0e5880891e6800e4
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3485
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>

POSIX: add posix_fallocate and a preallocate syscall

the preallocate syscall will call the preallocate filesystem hook, if available.

fix #6285

Change-Id: Ifff4595548610c8e009d4e5ffb64c37e0884e62d
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3382
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>

libroot/kernel: Implement MADV_FREE madvise() extension.

It allows an application to signal that it no longer needs the data in
the given address range and the underlying pages can be discarded and
reused elsewhere. This is finer grained than working with full areas
or mappings at a time and enables unmapping sections of partially used
mappings without giving up its address space.

Compared with punching holes into a mapping by "mapping over" with
PROT_NONE and MAP_NORESERVE, this has the obvious advantage of not
producing a lot of unused extra areas and saves the corresponding
resources. It is also a lot "lighter" of an operation than cutting
existing areas.

This introduces madvise() alongside the existing posix_madvise() to
allow for OS specific extensions. The constants for both functions are
aliased, the POSIX_MADV_* being a subset of the MADV_* ones without the
non-POSIX extensions. Internally posix_madvise() simply calls madvise().

MADV_FREE is commonly supported in other OSes with various subtle
semantic differences as to when pages are actually freed/cleared and how
or whether the pages are counted against the memory use of a process.
In the variant implemented here, pages are always immediately discarded
and memory counting is not altered. This behaviour should be considered
an implementation detail and may be altered later. The actual unmap and
discard could for example be delayed until pages are needed elsewhere to
reduce overhead in case of repeated discarding and remapping.

Note that MADV_FREE doesn't really align with the rest of the madvise()
API as it works like a command (i.e. discard these pages) and does not
add an attribute to the pages in the given range (i.e. mark these pages
for quick access from now on). As such, an MADV_FREE does not need to be
undone by setting a different advice later on, unlike how the other
flags work. This discrepancy may be the reason why it is not part of
POSIX.

Change-Id: Icc093379125a43e465dc4409d8f5ae0f64e107e0
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2844
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

Remove arch_get_caller

Use the gcc builtin instead, which generates more efficient code (it
saves a function call) and means less platform specific code to write
for us.

Change-Id: I1d55b5703027b2ea4ecde2438ea306bd4850eb32
Reviewed-on: https://review.haiku-os.org/c/haiku/+/1859
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

Update libroot stubs.

Update libroot stubs.

Update libroot stubs.

libroot: Add brk() and sbrk().

This commit replaces the placeholder implementation of sbrk(), which
operated on a process' heap, with real implementations of brk() and
sbrk() that adjust a process' program break.

* unistd.h: Add standard definitions of brk() and sbrk(); include
stdint.h for intptr_t.
* thread.cpp: Recognize RLIMIT_AS and RLIMIT_DATA resource limits
(both currently unlimited); order limit identifiers alphabetically.
* arch-specific.cpp: Remove sbrk_hook().
* malloc_debug_api.cpp: Remove sbrk_hook().
* unistd/Jamfile: Build brk.c instead of sbrk.c.
* unistd/brk.c: Add.
* unistd/sbrk.c: Delete (placeholder implementation).
* libroot_stubs.c: Remove sbrk_hook().
* libroot_stubs_legacy.c: Remove sbrk_hook().
* src/tests/.../posix/Jamfile: Build brk_test.c.
* brk_test.c: Add (simple unit test that demonstrates behaviour of
sbrk()).

Signed-off-by: Jérôme Duval <jerome.duval@gmail.com>

libroot_debug: Merge guarded heap into libroot_debug.

The individual debug heap implementations are now exposed via a
structure of function pointers and a common frontend dispatches the
malloc and malloc_debug APIs through them.

The MALLOC_DEBUG environment variable can be used to select the guarded
heap by adding 'g', otherwise the debug heap is used as the default.
Consequently the separate libroot_guarded is not needed anymore and has
been removed.

To allow the use of environment variables this early, init_env_post_heap
has been added and the heap dependent atfork() moved there. This allowed
to fold the code of init_heap_post_env into init_heap so the former has
been removed.

Add support for building <stubbed>libroot.so.

* <stubbed>libroot.so is a shared library which contains all the symbols
from libroot, but without any code. This library will be required by
the (to be introduced) stage0 of the bootstrap process, in order to
be able to link the shared gcc syslibs (libstdc++.so, libsupc++.so
and libgcc_s.so).

libroot_debug: Merge guarded heap into libroot_debug.

The individual debug heap implementations are now exposed via a
structure of function pointers and a common frontend dispatches the
malloc and malloc_debug APIs through them.

The MALLOC_DEBUG environment variable can be used to select the guarded
heap by adding 'g', otherwise the debug heap is used as the default.
Consequently the separate libroot_guarded is not needed anymore and has
been removed.

To allow the use of environment variables this early, init_env_post_heap
has been added and the heap dependent atfork() moved there. This allowed
to fold the code of init_heap_post_env into init_heap so the former has
been removed.

Add support for building <stubbed>libroot.so.

* <stubbed>libroot.so is a shared library which contains all the symbols
from libroot, but without any code. This library will be required by
the (to be introduced) stage0 of the bootstrap process, in order to
be able to link the shared gcc syslibs (libstdc++.so, libsupc++.so
and libgcc_s.so).