src-test2/include/pthread.h, branch release/11.3.0

MFC r337992, r338125:

2018-09-17T02:51:08Z

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 r331969, r332035:

2018-04-08T21:56:35Z

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. Hinted by: bionic (git 3f66e74b903905e763e104396aff52a81718cfde)

Revert r330897:

2018-03-29T02:50:57Z

This was intended to be a non-functional change. It wasn't. The commit message was thus wrong. In addition it broke arm, and merged crypto related code. Revert with prejudice. This revert skips files touched in r316370 since that commit was since MFCed. This revert also skips files that require $FreeBSD$ property changes. Thank you to those who helped me get out of this mess including but not limited to gonzo, kevans, rgrimes. Requested by: gjb (re)

MFC r313818:

2018-03-19T07:00:15Z

Small inclusion guard comment fix.

Partial merge of the SPDX changes

2018-03-14T03:19:51Z

These changes are incomplete but are making it difficult to determine what other changes can/should be merged. No objections from: pfg

MFC r312934:

2017-03-14T20:14:57Z

Make use of clang nullability attributes in C headers. Replace uses of the GCC __nonnull__ attribute with the clang nullability qualifiers. These are starting to get use in clang's static analyzer. Replacement should be transparent for developers using clang. GCC ports from older FreeBSD versions may need updating if the compiler was built before r312860 (Jan-27-2017). Hinted by: Apple's Libc-1158.20.4, Bionic libc Relnotes: yes

MFC r311012

2017-01-04T02:51:39Z

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. In general, the __nonnull() attribute has fulfilled its roll and will be replaced with the Clang _Nonnull qualifier in the future.

Add implementation of robust mutexes, hopefully close enough to the

2016-05-17T09:56:22Z

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 (some aspects) Tested by: pho Sponsored by: The FreeBSD Foundation

Implement process-shared locks support for libthr.so.3, without

2016-02-28T17:52:33Z

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 Tested by: pho Sponsored by: The FreeBSD Foundation

Make use of gcc attributes in some standard include headers.

2015-04-06T01:39:16Z

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