Add pthread_getname_np() and pthread_setname_np() aliases for
pthread_get_name_np() and pthread_set_name_np().

This re-applies r361770 after compatibility fixes.

Reviewed by: antoine, jkim, markj
T

Add pthread_getname_np() and pthread_setname_np() aliases for
pthread_get_name_np() and pthread_set_name_np().

This re-applies r361770 after compatibility fixes.

Reviewed by: antoine, jkim, markj
Tested by: antoine (exp-run)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D25117

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POSIX compliance improvements in the pthread(3) functions.

This basically adds makes use of the C99 restrict keyword, and also
adds some 'const's to four threading functions: pthread_mutexattr_getty

POSIX compliance improvements in the pthread(3) functions.

This basically adds makes use of the C99 restrict keyword, and also
adds some 'const's to four threading functions: pthread_mutexattr_gettype(),
pthread_mutexattr_getprioceiling(), pthread_mutexattr_getprotocol(), and
pthread_mutex_getprioceiling. The changes are in accordance to POSIX/SUSv4-2018.

Hinted by: DragonFlyBSD

Relnotes: yes
MFC after: 1 month
Differential Revision: D16722

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pthread.h: minor indentation cleanups.

No functional change.

X-MFC with: r331969

pthread.h: drop nullability attributes.

These have been found to be practically useless. We were actually
following the Android bionic library and had some interest in replicating
the same warnings

pthread.h: drop nullability attributes.

These have been found to be practically useless. We were actually
following the Android bionic library and had some interest in replicating
the same warnings and behaviour but Android has since removed them.

We are still keeping some uses of nullability attributes in other headers,
somewhat in line with Apple's libc.

MFC after: 1 week
Hinted by: bionic (git 3f66e74b903905e763e104396aff52a81718cfde)

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include: General further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manua

include: General further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

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Small inclusion guard comment fix.

Make use of clang nullability attributes.

Replace uses of the GCC __nonnull__ attribute with the clang nullability
qualifiers. The replacement should be transparent for clang developers as
the new q

Make use of clang nullability attributes.

Replace uses of the GCC __nonnull__ attribute with the clang nullability
qualifiers. The replacement should be transparent for clang developers as
the new qualifiers will produce the same warnings and will be useful for
static checkers but will not cause aggressive optimizations.

GCC will not produce such warnings and developers will have to use
upgraded GCC ports built with the system headers from r312538.

Hinted by: Apple's Libc-1158.20.4, Bionic libc
MFC after: 11.1 Release

Differential Revision: https://reviews.freebsd.org/D9004

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Remove some uses of the GCC __nonnull() attribute.

While the checks are considered useful, the attribute does dangerous
optimizations, removing NULL checks where they can be needed. Remove the
uses

Remove some uses of the GCC __nonnull() attribute.

While the checks are considered useful, the attribute does dangerous
optimizations, removing NULL checks where they can be needed. Remove the
uses of this attribute introduced in r281130: the changes were inspired on
Google's bionic where this attribute is not used anymore.

The __nonnull() attribute will be deprecrated from our headers and
replaced with the Clang _Nonnull qualifier in the future.

MFC after: 3 days

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Add implementation of robust mutexes, hopefully close enough to the
intention of the POSIX IEEE Std 1003.1TM-2008/Cor 1-2013.

A robust mutex is guaranteed to be cleared by the system upon either
thr

Add implementation of robust mutexes, hopefully close enough to the
intention of the POSIX IEEE Std 1003.1TM-2008/Cor 1-2013.

A robust mutex is guaranteed to be cleared by the system upon either
thread or process owner termination while the mutex is held. The next
mutex locker is then notified about inconsistent mutex state and can
execute (or abandon) corrective actions.

The patch mostly consists of small changes here and there, adding
neccessary checks for the inconsistent and abandoned conditions into
existing paths. Additionally, the thread exit handler was extended to
iterate over the userspace-maintained list of owned robust mutexes,
unlocking and marking as terminated each of them.

The list of owned robust mutexes cannot be maintained atomically
synchronous with the mutex lock state (it is possible in kernel, but
is too expensive). Instead, for the duration of lock or unlock
operation, the current mutex is remembered in a special slot that is
also checked by the kernel at thread termination.

Kernel must be aware about the per-thread location of the heads of
robust mutex lists and the current active mutex slot. When a thread
touches a robust mutex for the first time, a new umtx op syscall is
issued which informs about location of lists heads.

The umtx sleep queues for PP and PI mutexes are split between
non-robust and robust.

Somewhat unrelated changes in the patch:
1. Style.
2. The fix for proper tdfind() call use in umtxq_sleep_pi() for shared
pi mutexes.
3. Removal of the userspace struct pthread_mutex m_owner field.
4. The sysctl kern.ipc.umtx_vnode_persistent is added, which controls
the lifetime of the shared mutex associated with a vnode' page.

Reviewed by: jilles (previous version, supposedly the objection was fixed)
Discussed with: brooks, Martin Simmons <[email protected]> (some aspects)
Tested by: pho
Sponsored by: The FreeBSD Foundation

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Implement process-shared locks support for libthr.so.3, without
breaking the ABI. Special value is stored in the lock pointer to
indicate shared lock, and offline page in the shared memory is
alloca

Implement process-shared locks support for libthr.so.3, without
breaking the ABI. Special value is stored in the lock pointer to
indicate shared lock, and offline page in the shared memory is
allocated to store the actual lock.

Reviewed by: vangyzen (previous version)
Discussed with: deischen, emaste, jhb, rwatson,
Martin Simmons <[email protected]>
Tested by: pho
Sponsored by: The FreeBSD Foundation

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Make use of gcc attributes in some standard include headers.

The `nonnull' attribute specifies that some function parameters should be
non-null pointers. This is very useful as it helps the compile

Make use of gcc attributes in some standard include headers.

The `nonnull' attribute specifies that some function parameters should be
non-null pointers. This is very useful as it helps the compiler generate
warnings on suspicious code and can also enable some small optimizations.

Also start using 'alloc_size' attribute in the allocator functions.

This is an initial step to better integrate our libc with the compiler:
these attributes are fully supported by clang and they are also useful
for the static analyzer.

Note that due to some bogus internal procedure in the way gcc ports
are built they may require updating if they were built before r280801.

Relnotes: yes
Hinted by: Android's bionic libc
Differential Revision: https://reviews.freebsd.org/D2107

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Clean some spaces vs tabs.

No, this file doesn't conform with KNF at all.

Temporarily revert 280458.

GCC is still carries an old version of cdefs.h which doesn't
accept multiple parameters for the nonnull attribute.

Since this issue probably affects many ports in the tre

Temporarily revert 280458.

GCC is still carries an old version of cdefs.h which doesn't
accept multiple parameters for the nonnull attribute.

Since this issue probably affects many ports in the tree
we will revert it for now until gcc gets fixed.

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Introduce nonnull attributes in the signal and pthread headers.

The `nonnull' attribute specifies that some function parameters should be
non-null pointers. This is very useful as it helps the comp

Introduce nonnull attributes in the signal and pthread headers.

The `nonnull' attribute specifies that some function parameters should be
non-null pointers. This is very useful as it helps the compiler generate
warnings on suspicious code and can also enable some small optimizations.
In clang this is also useful for the static analyzer.

While we could go on defining this all over the tree, it only
makes sense to annotate a subset of critical functions.

Hinted by: Android's bionic libc
Differential Revision: https://reviews.freebsd.org/D2101

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Add lock annotations to the header files of our threading libraries.

This change extends all of the functions present in the <pthread.h> and
<threads.h> headers to have lock annotations. This will a

Add lock annotations to the header files of our threading libraries.

This change extends all of the functions present in the <pthread.h> and
<threads.h> headers to have lock annotations. This will allow Clang to
warn about the following:

- Locking a function twice,
- Unlocking a function without a mutex being locked,
- Forgetting to unlock a mutex before returning,
- Destroying or reinitializing a mutex that is currenty locked,
- Using an unlocked mutex in combination with a condition variable.

Enabling these annotations already allowed me to catch a bug in one of
our userspace tools (r270749).

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Add a dummy statement to the beginning of the pthread_cleanup_pop() macro
to allow a call of the macro to be labelled as in:

label:
pthread_cleanup_pop();

Reviewed by: imp
MFC after: 3 days

Remove leftover for r214093.

Add pthread_rwlockattr_setkind_np and pthread_rwlockattr_getkind_np, the
functions set or get pthread_rwlock type, current supported types are:
PTHREAD_RWLOCK_PREFER_READER_NP,
PTHREAD_RWLOCK_P

Add pthread_rwlockattr_setkind_np and pthread_rwlockattr_getkind_np, the
functions set or get pthread_rwlock type, current supported types are:
PTHREAD_RWLOCK_PREFER_READER_NP,
PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP,
PTHREAD_RWLOCK_PREFER_WRITER_NP,
default is PTHREAD_RWLOCK_PREFER_WRITER_NONCECURSIVE_NP, this maintains
binary compatible with old code.

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In current code, statically initialized and destroyed object have
same null value, the code can not distinguish between them, to
fix the problem, now a destroyed object is assigned to a non-null
valu

In current code, statically initialized and destroyed object have
same null value, the code can not distinguish between them, to
fix the problem, now a destroyed object is assigned to a non-null
value, and it will be rejected by some pthread functions.
PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP is changed to number 1, so that
adaptive mutex can be statically initialized correctly.

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Fix the visibility of several prototypes. Also move pthread_kill() and
pthread_sigmask() to signal.h. In principle, this shouldn't break anything,
since they're already in signal.h on other systems,

Fix the visibility of several prototypes. Also move pthread_kill() and
pthread_sigmask() to signal.h. In principle, this shouldn't break anything,
since they're already in signal.h on other systems, and the FreeBSD
manpage says that both pthread.h and signal.h need to be included to
get these functions.

Add a hack to declare pthread_t in the P1003.1-2008 namespace
in signal.h.

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Make pthread_cleanup_push() and pthread_cleanup_pop() as a pair of macros,
use stack space to keep cleanup information, this eliminates overhead of
calling malloc() and free() in thread library.

Dis

Make pthread_cleanup_push() and pthread_cleanup_pop() as a pair of macros,
use stack space to keep cleanup information, this eliminates overhead of
calling malloc() and free() in thread library.

Discussed on: thread@

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Add POSIX pthread API pthread_getcpuclockid() to get a thread's cpu
time clock id.

Add a new "non-portable" mutex type, PTHREAD_MUTEX_ADAPTIVE_NP. This
is also implemented in glibc and is used by a number of existing
applications (mysql, firefox, etc).

This mutex type is a defaul

Add a new "non-portable" mutex type, PTHREAD_MUTEX_ADAPTIVE_NP. This
is also implemented in glibc and is used by a number of existing
applications (mysql, firefox, etc).

This mutex type is a default mutex with the additional property that
it spins briefly when attempting to acquire a contested lock, doing
trylock operations in userland before entering the kernel to block if
eventually unsuccessful.

The expectation is that applications requesting this mutex type know
that the mutex is likely to be only held for very brief periods, so it
is faster to spin in userland and probably succeed in acquiring the
mutex, than to enter the kernel and sleep, only to be woken up almost
immediately. This can help significantly in certain cases when
pthread mutexes are heavily contended and held for brief durations
(such as mysql).

Spin up to 200 times before entering the kernel, which represents only
a few us on modern CPUs. No performance degradation was observed with
this value and it is sufficient to avoid a large performance drop in
mysql performance in the heavily contended pthread mutex case.

The libkse implementation is a NOP.

Reviewed by: jeff
MFC after: 3 days

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Add prototype for following functions, plus tab fixes.
pthread_condattr_getpshared
pthread_condattr_setpshared
pthread_mutexattr_getpshared
pthread_mutexattr_setpshared

Improve POSIX conformance:
- Don't pollute the namespace by including <sys/types.h>, <sys/time.h>,
<sys/signal.h> and <limits.h>. Use __MINSIGSTKSZ and __ULONG_MAX from
<machine/_limits.h>, __si

Improve POSIX conformance:
- Don't pollute the namespace by including <sys/types.h>, <sys/time.h>,
<sys/signal.h> and <limits.h>. Use __MINSIGSTKSZ and __ULONG_MAX from
<machine/_limits.h>, __sigset_t from <sys/_sigset.h> instead.
- Include <time.h> because POSIX says we have to.

PTHREAD_{DESTRUCTOR_ITERATIONS,KEYS_MAX,STACK_MIN,THREADS_MAX} should
eventually move to <limits.h> but are left here for now.

Discussed on: standards@, threads@

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